Progress in Solar/Stellar Physics with Helio- and Asteroseismology

The 61st Fujihara Seminar

Progress in solar/stellar physics with helio- and asteroseismology

2011 March 13-17

The Prince Hakone, Japan

The Fujihara Foundation of Science Organizers Hiromoto Shibahashi Masao Takata Department of Astronomy, University of Tokyo, Tokyo, Japan

Scientific Organizing Committee C. Aerts (Belgium) L. A. Balona (South Africa) T. R. Bedding (Australia) J. Christensen-Dalsgaard (Denmark) G. Fontaine (Canada) L. Gizon (Germany) J. A. Guzik (U.S.A.) G. Houdek (Austria) C. S. Jeffery (U.K.) S. D. Kawaler (U.S.A.) A. G. Kosovichev (U.S.A.) D. W. Kurtz (U.K.) G. Mathys (Chile) P. L. Pall´e(Spain) H. Shibahashi (Chair: Japan) M. J. Thompson (U.S.A.) S. Vauclair (France) Preface

It was a little bit more than two decades ago that an international conference, “Progress of seismol- ogy of the Sun and stars” was held at this place, Hakone, in 1989, as the “Oji Seminar”, sponsored by the Fujihara Foundation of Science (see the proceedings published in 1990 by Springer as “Lec- ture Notes in Physics” 367). At that time, helioseismology was growing fast from its infant stage, and we believe that the seminar contributed to further brilliant success of helioseismology, which led to the progress of solar physics by unveiling various physics from the invisible interior of the Sun. Since then, helioseismology has achieved outstanding success with great impact on various aspects of astrophysics. The discovery of very small amplitude pulsations in the Sun has raised a question concerning the concept of pulsating and non-pulsating stars. Pulsations, at least with small am- plitudes, have been ubiquitously found among stars in general. Asteroseismology, a seismological approach to stars in general, is now activated as a new frontier of astrophysics and is going to develop rapidly following the success of helioseismology. It is our great pleasure to have, in such a circumstance, an opportunity for many active researchers working in the field of helio- and asteroseismology to come together from all over the world to Hakone, as the Fujihara Seminar, sponsored by the Fujihara Foundation of Science again. We deeply appreciate the Fujihara Foundation of Science for its generous financial support, which enabled us to have this second helio-/asteroseismology conference held at Hakone. Let us explain briefly about the Fujihara Foundation of Science and its activities by quoting descriptions from the web page of the Foundation. The Foundation was founded by Ginjiro Fujihara (1869.7.25-1960.3.17), who is known as the “King of Paper-making of Japan”. He had always worked to help make Japan one of the world’s leading nations based on science and technology. Among the great contributions he performed to achieve this objective was an exceptionally colossal donation made in 1938 to The University of Tokyo and some other major universities under the name of the former Oji Paper Co., Ltd., for which he worked as the presidency since 1898. This colossal contribution was made to encourage science education in Japanese universities, in commemoration of the 5th anniversary of the merger of three paper manufacturing companies (Oji Paper Co., Ltd, Fuji Paper Co., Ltd., and Karafuto Industry Corp.). In the same year when he retired as president of the former Oji Paper Co., Ltd., Mr. Fujihara founded an educational institution called the Fujihara Institute of Technology, which is currently the Faculty of Science and Technology of Keio University, out of his own pocket. At the age of 90 (1959), he founded The Fujihara Foundation of Science again out of his own pocket to encourage activities in science and technology in Japan in the future. To achieve Mr. Fujihara’s cherished desire, the Foundation has carried out two key missions: the Fujihara Award and the Fujihara Seminar. The Fujihara Seminar was started in 1974 to support annual international seminars as a part of the events commemorating the 100th anniversary of the former Oji Paper Co., Ltd. Sixty seminars have been funded as of 2010. With the wish for contribution to the progress of science and technology through international exchange among scientists, the Foundation is now funding two seminars in a year. One of the policies of the Fujihara Seminar is that all the participants stay at the same hotel to facilitate the informal exchange of ideas in a relaxed atmosphere after the formal sessions of the conference. As a consequence, the number of participants is limited to 100 at most. The Hakone conference held in 1989 was the 29th seminar, though the seminar was at that time named “Oji Seminar”. The present conference is organized as the 61st Fujihara Seminar, an international conference on helio- and asteroseismology. The prime purpose of this conference is to bring together active

1 researchers in the field of helio- and asteroseismology and related fields to share their latest results, to discuss future approaches and to exchange ideas: How do helio- and asteroseismology help to investigate physical processes in stars? How useful are helio- and asteroseismology to unravel unsolved problems in solar and stellar physics? What kinds of new physics have been derived from helio- and asteroseismology? What is expected in the future? Hakone is an excellent resort area of scenic beauty with historic and cultural interest. The Hakone Prince Hotel, at which the Seminar is now being held, is located on the shore of Lake Ashi with a view of Mt. Fuji. We hope that staying together in such a good environment facilitates communication and lively discussions to inspire new ideas, and that the conference will be fruitful to all the participants.

Hiromoto Shibahashi and Masao Takata

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Programme

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4 • Sunday: March 13 – Hotel check-in / Poster hanging – 18:00- Welcome reception

• Monday: March 14 – 09:00-09:10 S. Ban (Executive Director of the Fujihara Foundation of Science) : Opening address

I. Impacts of seismic investigations on solar/stellar physics (a) physics understood/expected from helio- and asteroseismology

– 09:10-09:40 (R) H. Saio : Physics of stars understood/expected from asteroseismology – 09:40-10:00 Y. Lebreton : Asteroseismology, an essential tool towards accurate stellar ages – 10:00-10:30 (R) G. Fontaine : The physics of pulsating white dwarf stars

– 10:30-11:00 break

– 11:00-11:30 (R) D. O. Gough : Physics of the Sun gleaned from helioseismology – 11:30-11:50 A. Baglin : CoRoT highlights, impacts on stellar physics – 11:50-12:10 J. Christensen-Dalsgaard : Asteroseismology with the Kepler mission – 12:10-12:30 W. J. Chaplin : Recent progress and future prospects for inference on solar- type stars

– 12:30-14:00 lunch

– 14:00-14:20 I. W. Roxburgh : Phase shift asteroseismological diagnostics for solar like stars

(b) asteroseismic determination of stellar parameters

– 14:20-14:40 T. Appourchaux : The challenge of fitting many stellar power spectra with Kepler – 14:40-15:00 T. S. Metcalfe : First results from the asteroseismic modeling portal – (P01) S. G. Korzennik : A determination of high degree mode parameters based on MDI observations – (P02) S. K. Randall : Pulsational mode identification based on chromatic amplitude behaviour: recent results for rapidly oscillating subdwarf B stars – (P03) M. Papar´o: Borderline between asteroseismology and stellar activity

(c) new observational findings and other enigmatic phenomena

– 15:00-15:20 C. Aerts : Seismic diagnostic tools for hybrid B-type pulsators with slow to moderate rotation – 15:20-15:40 G. Handler : Hybrid pulsators among A and F stars

5 – 15:40-16:20 break and poster viewing

– 16:20-16:40 T. R. Bedding : Mixed modes in subgiants and red giants – 16:40-17:00 J. Montalb´an: Oscillation spectra of red giant stars: the predictive power of dipole modes – 17:00-17:20 S. Hekker : Characterisation of red-giant stars in the public Kepler data – 17:20-17:40 M. P. Di Mauro : Detailed study of the internal structure of the red-giant star KIC 4351319 observed with Kepler – 17:40-18:00 D. W. Kurtz : The first evidence for multiple pulsation axes: a new roAp star in the Kepler field, KIC 10195926 – 18:00-18:20 W. W. Weiss : The enigmatic pulsation of γ Equ – (P04) S. Hekker : Asteroseismic inferences on red giants in open clusters NGC 6791, NGC 6819 and NGC 6811 using Kepler – (P05) H. Ando : Okayama project: solar-like oscillations in sub-giants and giants – (P06) A. Kanaan : Pulsating white dwarfs in globular clusters – (P07) G. Vauclair : Period and amplitude changes in the GW Vir variable star (PG 1159-type) PG 0122+200: evidence for resonant coupling – (P08) M. Sachkov : Long term spectroscopic study of the excited mode stability in the roAp star γ Equ – (P09) M. Sch¨oller: Multiplicity of rapidly oscillating Ap stars

• Tuesday: March 15 Session I.(c) continued

– 09:00-09:20 J. Matthews : Pulsational “Rosetta Stones”? MOST seismology of δ Scuti and γ Doradus stars – 09:20-09:40 L. A. Balona : New insights into Gamma Doradus pulsation using Kepler public archive data – 09:40-10:00 A. Bischoff-Kim : Asteroseismology of rich pulsating white dwarfs – 10:00-10:20 S. Charpinet : The helium cores of extreme horizontal branch stars scruti- nized through g-mode seismology with Kepler and CoRoT – (P10) A. Baran : Suhora survey - searching for M dwarf pulsators – (P11) A.´ S´odor: The Konkoly Blazhko Survey 2 – (P12) S. Mathur : Seismic analysis of 4 solar-like stars observed during more than 8 months by Kepler mission

– 10:20-10:50 break

II. Solar and stellar activity (a) the solar dynamo viewed from helioseismology

– 10:50-11:20 (R) T. Sakurai : Helioseismology, solar dynamo, and magnetic helicity

6 – 11:20-11:50 (R) A. G. Kosovichev : A paradigm shift in solar dynamo and helioseismic constraints – 11:50-12:10 T. L. Duvall, Jr. : Time-distance analysis of deep solar convection – 12:10-12:30 D.-Y. Chou : Measurements of solar acoustic waves scattered by sunspots

– 12:30-14:00 lunch

– 14:00-14:20 J. Zhao : Interaction of helioseismic waves with sunspots: observations and numerical MHD simulations – 14:20-14:40 S. Ilonidis : Detecting subsurface signatures of emerging solar active regions – (P13) M. Kubo : Magnetic flux transportation from decaying sunspot – (P14) L. Gizon : Adjoint tomography of the Sun

(b) magnetic fields and stellar activity across the H-R diagram

– 14:40-15:10 (R) G. Mathys : Magnetic field and stellar activitiy across the H-R diagram – 15:10-15:30 S. Hubrig : First magnetic field models for recently discovered magnetic β Cephei and slowly pulsating B stars – 15:30-15:50 S. Mathur : Investigating stellar activity with CoRoT data

– 15:50-16:30 break and poster viewing

– 16:30-16:50 R. A. Garc´ıa: Fast rotating solar-like stars from the first year of Kepler observations – 16:50-17:10 S. O. Kepler : The ZZ Ceti instability strip and magnetic white dwarfs in the SDSS – (P15) F. Baudin : Measurement of magnetic activity in a large stellar sample from CoRoT observations – (P16) I. S. Savanov : Stellar activity of the seismic solar-like COROT targets – (P17) S. Hubrig : The roAp star with the strongest magnetic field: the characterization of HD 154708 – (P18) S. Hubrig : First detection of a magnetic field in the fast rotating pulsator ζ Ophiuchi

(c) the cause of solar activity viewed from helioseismology

– 17:10-17:40 (R) F. Hill : Helioseismic observations of solar convection zone dynamics and their relationship to solar activity – 17:40-18:00 S. Basu : How different was the last solar minimum? – 18:00-18:20 S. G. Korzennik : The solar rotation and its evolution during cycle 23

• Wednesday: March 16 Session II.(c) continued

– 08:45-09:05 J. Schou : Helioseismic measurements of the torsional oscillation

7 – 09:05-09:25 K. Nagashima : Dynamics in the polar regions of the Sun – (P19) S. Turck-Chi`eze: Solar Doppler velocity global oscillations of low degrees: the status of GOLF-NG

III. Challenging observations (a) Instrumentation

– 09:25-09:45 P. L. Pall´e: Challenges in the development of new instrumentation for helio- and asteroseismology ? – (P20) E. Kambe : Development of the fiber-link between Okayama 1.88 m telescope and high dispersion echelle spectrograph, HIDES

(b) Challenging observations

– 09:45-10:05 S. Tsuneta : JAXA Solar & helio physics roadmap 2011-2025

– 10:05-10:30 break

IV. Abundance determination and seismic investigation of chemical stratification (a) impact of the revised solar abundances on helio-/asteroseismology

– 10:30-11:00 (R) N. Grevesse : The new solar chemical composition – (P21) S. Turck-Chi`eze: Radiative properties of stellar plasma: the challenges we need to face

(b) seismic investigation of chemical stratification inthe Sun and stars

– 11:00-11:30 (R) S. Th´eado: Seismic investigation of chemical stratification in stars – 11:30-11:50 C. S. Jeffery : Asteroseismology and chemical stratification in hot subdwarfs: the remarkable case of the zirconium star LS IV−14◦116 – 11:50-12:10 H. Hu : Radiative levitation in subdwarf B stars

– 12:10-13:30 lunch

• Wednesday: March 16 afternoon

– Excursion

• Thursday: March 17 Session IV.(b) continued

– 09:00-09:20 G. Alecian : Stratification of elements in HgMn stars and their observational effects – 09:20-09:40 S. Vauclair : Asteroseismology of exoplanets-host-stars: the helium problem and other associate effects

8 V. Hydrodynamics (a) solar and stellar hydrodynamics: global dynamics, large-scale dynamics, evolution of the solar/stellar internal rotation

– 09:40-10:10 (R) A. S. Brun : Towards a 3-D MHD model of the whole solar interior and its tachocline – 10:10-10:30 S. Turck-Chi`eze: The long term dynamics of the radiative zone associated to new results from SOHO and young analogs – (P22) S. Couvidat : Can the interaction of torsional oscillations with a sunspot generate Rossby waves? – (P23) J. Leibacher : Meridional flow measurements from GONG – (P24) A. Nitta : Time series UV spectroscopy of GD358 – (P25) A. H. C´orsico: Stellar differential rotation with depth: the case of the pulsating pre-white dwarf PG 0122+200

– 10:30-11:00 break

(b) solar and stellar magnetohydrodynamics: diffusion, mixing, convection, turbulence, mag- netic structures

– 11:00-11:20 R. F. Stein : Magneto-convection simulation data for local helioseismology analysis – 11:20-11:40 J. Toomre : New era in 3-D modelling of convection and magnetic dynamos in younger suns and F stars – 11:40-12:00 M. J. Thomson : 3D ring inversions of local helioseismic data: probing flows around sunspots – (P26) S. J. Kleinman : Pulsation convection modeling of the DAV white dwarf star, G29-38, in different states – (P27) I. N. Kitiashvili : Self-organization of solar turbulent convection in magnetic field – (P28) I. N. Kitiashvili : Radiative hydrodynamics simulations of turbulent convection for Kepler target stars – (P29) S. Mathur : Investigating the properties of convection/granulation in the red giants observed by Kepler

– 12:00-13:30 lunch

VI. Oscillations and excitation mechanisms (a) physical causes and excitation mechanisms of oscillations in various types of stars

– 13:30-14:00 (R) G. Houdek : Driving mechanisms of stellar pulsations – 14:00-14:20 D. Stello : Amplitudes of solar-like oscillations in red giant stars: constraints from open clusters observed by Kepler – 14:20-14:40 I. N. Kitiashvili : Mechanism of acoustic waves excitation by turbulent convection and vortex dynamics – 14:40-15:00 M.-J. Goupil : Impact of rotation on seismic models for 2 COROT stars HD49933 and HD181420

9 – 15:00-15:20 K. Belkacem : On the relation between the cut-off frequency and the fre- quency of the maximum in the power spectrum in solar-like stars

– 15:20-16:00 break and poster viewing

– 16:00-16:20 J. Leibacher : Solar atmospheric seismology with HMI and AIA onboard SDO – 16:20-16:40 F. Baudin : Amplitudes of solar-like oscillations in hot stars: observations and predictions – (P30) T. R. Bedding : Amplitudes of solar-like oscillations: a new scaling relation – (P31) M. Godart : Theoretical instability domains in the upper part of the HR diagram – (P32) J. P. Marques : The effect of the initial conditions on stellar rotation, and its impact on oscillation frequencies

– (P33) R.-M. Ouazzani : Pulsations of an evolved self-consistently distorted 2 M⊙ – (P34) J. Naito : Numerical simulations of line-profile variation beyond a single-surface approximation

(b) Oscillations of rotating stars, metal poor stars, ...

– 16:40-17:00 J. Ballot : Gravity modes in rapidly rotating stars – 17:00-17:20 H. Shibahashi : Influence of metallicity on stellar structure and oscillatory properties of stars – (P35) H. Ishimatsu : Traditional approximation for low-frequency modes in rotating stars – (P36) U. Lee : Nonlinear coupling coefficient for low frequency modes in rotating stars – (P37) T. Sonoi : Vibrational instability of metal poor stars due to ε-mechanism – (P38) H. Saio : A comparison of oscillation frequencies of rotating stars obtained by one- and two-dimensional calculations – (P39) M. Takata : An approach to the exact classification of adiabatic eigenmodes of stars – (P40) A. H. C´orsico: Constraining the axion mass through the asteroseismology of ZZ Ceti stars – (P41) R. Hamerly : Dark matter and its effects on helioseismology

• Thursday: March 17 evening

– 19:00- Closing banquet

• Friday: March 18

– Hotel check-out

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Abstracts

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12 Seismic diagnostic tools for hybrid B-type pulsators with slow to moderate rotation C. Aerts1,2, M.-A. Dupret3, P. Degroote1 & M. Briquet1 1Instituut voor Sterrenkunde, K.U.Leuven, Belgium 2Department of Astrophysics, Radboud University Nijmegen, the Netherlands 3Institut d ’Astrophysique et de G´eophysique,University of Li`ege,Belgium

With the CoRoT and Kepler missions in full operation, it has become clear that our view of B-type pulsators changed quite drastically. Seismic modelling had previously been achieved for several β Cep stars, based on the detection of a few low order p- and g-mode frequencies with periods of hours and their rotational splitting, or from empirical mode identification based on multicolour photometry and/or high resolution spectroscopy. Lack of mode identification and the density of the g-mode spectrum prevented seismic modelling of slowly pulsating B stars (SPBs) so far. The CoRoT and Kepler space photometry led to the discovery of several hybrid B-type pulsators, with mainly dominant high-order g-mode frequencies and a few low-amplitude low-order p-modes. Such a g-mode spectrum is according to those already found previously for SPBs from ground- based data, but with a much higher number of significant frequencies thanks to the far better signal-to-noise ratios of the space photometry. Given this change of pulsation information, we need to define new types of diagnostic tools to interpret the space data. We present several such diagnostics based on pulsational computations, taking into account the Coriolis force in the traditional approximation, which is an excellent as- sumption in the case of slow rotators with high-order gravity modes. We show that frequency matching is not a good approach for g-mode pulsators. We illustrate our tools by applying them to some case studies of hybrid B-type pulsators. Contact and/or more info: [email protected], http://www.ster.kuleuven.be/PROSPERITY/

13 Stratification of elements in HgMn stars and their observa- tional effects G. Alecian Observatoire de Paris - CNRS, France

Mercury-manganese stars (HgMn) are wellknown chemically peculiar stars (a subgroup of Ap stars), which have been extensively studied in the framework of the atomic diffusion theory. According to the diffusion model, the observed large abundance anomalies are consequences of chemical stratification in the atmospheres of these stars. All the elements are affected. However, the stratification process does not only concern the atmospheres of HgMn stars, but also their internal layers. Such chemical stratifications have several consequences. The most trivial one is the impact on the abundance derminations and their interpretation. Another consequence is a significant modification of the Rosseland opacity of internal layers, due to the enhancement of iron peak elements. This necessarily affects the internal structure and asteroseismic properties of these stars. I will present the most recent diffusion computations for HgMn stars and discuss the possible relation to the photometric variations detected for some HgMn stars in CoRot lightcurves.

14 Okayama project: solar-like oscillations in sub-giants and gi- ants Hiroyasu Ando1, Eiji Kambe2 & Bun’ei Sato3 1National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1,Osawa, Mitaka, Tokyo, 181-8588, Japan 2Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, National In- stitutes of Natural Sciences, 3037-5, Honjo, Kamogata, Asakuchi,Okayama 719-0232, Japan 3Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan

We started an investigation of solar-like oscillations in the late type stars as Okayama project at Okayama Astrophysical Observatory. At the moment, we conducted the precise radial-velocity measurements of 2 sub-giants (Procyon and κ CrB) and 4 giants (11Com, ζ Hya, ϵ Tau, and η Her). The short-term variations with amplitudes, 1-7m/s and periods, 3-10 hours were detected. A period analysis shows that the individual power distribution is in a Gaussian shape and their peak frequencies (νmax) are in a good agreement with the prediction by the scaling law. We picked up significant frequency peaks more than 3 σ, and determined the large frequency separation by constructing highest peak distribution of collapsed power spectrum, which is also in good agree- ment with what the scaling law for the large separation predicts. Echelle diagrams of oscillation frequency were created based on the extracted large separations, which is very useful to clarify the properties of oscillation modes. In these echelle diagrams, odd-even mode sequences are clearly seen. Therefore, it is certain that in these late type stars, non-radial modes are detected in addition to radial mode. As a consequence, these properties of oscillation modes are shown to follow what Dziembowski (2001) and Dupret et al.(2009) theoretically predicted.

15 The challenge of fitting many stellar power spectra with Ke- pler T. Appourchaux1 and the WG#1 members of Kepler 1Universit´eParis Sud, France

The Kepler mission has been now in operation for more than a year. Several hundreds of solar-like stars are at our disposal for deriving the characteristics of their p-mode spectra. The spectra are fitted by different fitters using different assumptions. The current challenge is to provide an homogenous data set for the modellers where all p-mode parameters are agreed by the different fitters. We will show the various chain of thoughts that let us to choose one strategy vs others. The application to Kepler of the current strategy will be explained, with future application to the PLATO mission.

16 CoRoT highlights, impacts on stellar physics Annie Baglin & Eric Michel Observatoire de Paris, France

After more than 4 years in orbit CoRoT has observed already 140 bright stars(in the so called seismology field) and more than 100,000 fainter ones (in the so-called exoplanet field). Spanning a large part of the HR diagram. Time series cover up to 160 days with a duty cycle generally larger than 90%. The data are photon noise limited over most of the magnitude range. These observations are going on, since the mission was extended for 3 more years till 2013. These data of unprecedented quality revealed new behaviors, some expected for a long time, some others completely new. A large part of the set is still under analysis but the significant number of objects already studied show that the seismic parameters are accessed at the precision expected for interpretation. Beyond this technical and observational success, a main part of our objective is to provide new observables and use them to address open questions of stellar structure and evolution. The number of interpretation studies is progressing and is expected to progress more and more rapidly in the coming years. Present results concern various aspects. The extension of convective cores has been evaluated in different types of stars from massive ones to solar like objects on and off the main sequence. The structure of near surface convective zones can be accessed through direct measurements as well as various indicators as amplitudes of modes and granulation. Magnetic activity produces modulations of the light curves used for spot modelling, and even variations of seismic parameters. Seismic perturbations due to mass loss have also been detected in hot stars. Population studies become possible through the statistical behavior of the seismic indicators in different regions of the sky. Though definitive conclusions will need cross-comparison of results on the larger set of stars being built, it is already interesting to consider the various existing results to illustrate how they open questions of stellar physics and our scientific objectives.

17 Gravity modes in rapidly rotating stars J. Ballot1, F. Lignieres` 1, V. Prat1, D. R. Reese2 & M.Rieutord1 1IRAP, Universit´ede Toulouse, CNRS, 31000 Toulouse, France 2LESIA, Univ. Pierre et Marie Curie, Univ. Denis Diderot, Observatoire de Paris, 92195 Meudon, France

We have used the Two-dimensional Oscillation Program (TOP) to explore the effects of rapid rota- tion on gravity modes in stars. We performed complete computations of gravity modes, including the Coriolis force, the centrifugal distortion, and compressible effects, in 2D distorted polytropic models of stars. We started with the modes l = 1, n = 1 ∼ 14, and l = 2 ∼ 3, n = 1 ∼ 5, 16 ∼ 20 of a nonrotating star, and followed these modes by increasing the rotation rate up to 70% of the break-up rotation rate. We then derived perturbative coefficients and determined the domains of validity of the perturbative methods. We also analysed the evolution with rotation of period spacings and compared the laws we get with results obtained with the traditional approximation. Finally, we study the full structure of the g-mode spectrum at a given rotation —representative for a gamma Doradus star—, and start to classify modes by using the asymptomatic development derived by Prat et al. (in preparation).

18 New insights into Gamma Doradus pulsation using Kepler public archive data L. A. Balona South African Astronomical Observatory, South Africa

Visual classification of over 10,000 stars in the Kepler public database has revealed stars which show a characteristic Blazhko effect (beating) in the light curve. The light curves are asymmetric with larger variation in maximum brightness than in minimum brightness. These stars seem to be an extension of a more numerous group also showing the Blazhko effect, but with more symmetric light curves. Both types of star fall in the region of the HR diagram where gamma Dor stars are found and we therefore identify them as gamma Dor pulsators. These stars are almost mono- periodic, the beating effect arising from only one or two rather broad peaks in the periodogram. The very limited mode selection is a puzzle. If one assumes that the pulsation period is close to the rotational period, the resulting distribution of equatorial velocities is similar to those of F1-F5 stars in the general field. This suggests that mode selection is related to rotation. Finally, we find a much smaller number of gamma Dor stars with multiple periods and therefore different mode selection characteristics.

19 Suhora survey - searching for M dwarf pulsators Andrzej Baran1,2, Jerzy Krzesinski1 & Steve Kawaler2 1Cracow Pedagogical University, Poland 2Iowa State University, USA

We present the first results of our M dwarf survey in search for stellar pulsation in low mass main sequence stars. Theoretical calculations made by Steve Kawaler predict that ε-mechanism might drive a fundamental radial mode in these stars and therefore pulsations could be observed photometrically. Although M dwarfs are known for their flare and spot activity, they have not yet been the subject of dedicated time-series surveys for pulsation. In this presentation we include the light curves along with amplitude spectra and Phase Dispersion Minimization analysis of a dozen of M red dwarfs, which have been observed during the first year of our survey. None of them seems to be a pulsating star. As a by-product of our search, we have detected many flares of M dwarfs and variation in seven field stars. Altogether, the survey will last for two more years and during that period more than a hundred of M0 - M6 type main sequence stars will be observed.

20 How different was the last solar minimum? Sarbani Basu1, William J. Chaplin2, Yvonne Elsworth2, Anne-Marie Broomhall2 & Eliza- beth M. Jarvis2 1Yale University, USA 2University of Birmingham, UK

The activity minimum between solar cycles 23 and 24 has been exceptional in its quietness. It had the lowest sustained 10.7 cm flux since since observation of this proxy began in 1947. There have been other differences, such as the fact that the solar corona did not reach the simple dipolar shape usually seen during solar minima, and the polar field during the cycle 24 minimum was lower than that of the cycle 23 minimum. The size of supergranules have also been reported to be smaller during the cycle 24 minimum. The “peculiarity” of the cycle 24 minimum was not confined to the solar surface – the internal dynamics of the Sun has also been found to be very different for the minimum of cycle 24 compared with that of cycle 23. Thus far there have been only preliminary attempts to determine whether there were differences in the structure of the Sun during the cycle 24 minimum compared with the cycle 23 minimum. Basu et al. (2010), using data from the Birmingham Solar Oscillations Network showed that the frequency differences between the two minima indicate differences in structure that are quite deep. We have extended this work to determine the nature of the differences in solar structure between the minima of cycles 24 and 23. We use a hybrid forward-modelling and fitting method to determine the differences since direct inversions of only low-degree modes do not yield results for the outer layers of the Sun.

21 Amplitudes of solar-like oscillations in hot stars: observations and predictions F. Baudin1 & K. Belkacem2 1Institut d’Astrophysique Spatiale, Orsay, France 2Universit´ede Lie`ge,Belgium

Solar-like oscillations have been detected in hot stars for the first time in HD180642, a β Cephei star observed by CoRoT (Belkacem et al., 2009, Science, 324, 1540). Then, at least another occurence of such oscillations in a hot star has been publi shed by DeGroote et al. (2010, A&A, 519, A38) in HD46149, an O star, again observed by CoRoT. Some other cases are expected from the wealth of data provided by Kepler. The presence of stochastically excited oscillation in hot stars confirms the existence of convection inside the star. In the case of of HD180642, two cases were considered from a theoretical point of view (Belkacem, Dupret & Noels, 2010, A&A, 510, A6): oscillation driving by the convective core or by the convection zone related to the Fe ionization zone. We present in this work measurements of the amplitude of the solar-like oscillations in HD180642 and HD46149. These amplitudes bring constraints that can be compared to predictions of Belka- cem, Dupret & Noels and thus on the location of oscillation driving. In addition, observed differ- ences in oscillation properties in HD180642 and HD46149 are interpreted in terms of the age of the stars.

22 Measurement of magnetic activity in a large stellar sample from CoRoT observations J.-C. Hulot1, F. Baudin1∗ & B. Mosser2 1 Institut d’Astrophysique Spatiale, Orsay, France 2 LESIA/Observatoire de Paris, Meudon, France

Thanks to the high precision of space-borne photometers like CoRoT, it becomes possible to detect magnetic spots on stellar surfaces. These spots can be detected directly in the light-curve of the star (e.g. Lanza et al. 2009, A&A, 506, 255; Mosser et al. 2009, A&A, 506, 245) or indirectly in the low frequency part of the Fourier spectrum of the light-curve (Hulot et al., 2011, A&A, submitted). We present in this work the application of the latter technique to a sample of 400 stars observed by CoRoT. Activity is detected in a large number of stars (more than 300) with a level ranging from moderately active stars to stars less active than the Sun. This microvariability due to transiting stellar spots is quantified and related to star’s properties: effective temperature and rotation period. The Rossby number, combining the rotation period and convective properties of the star is also used and shows a clear (anti)correlation with the level of activity observed in our sample.

∗presenter

23 Mixed modes in subgiants and red giants Tim Bedding1 and numerous members of the Kepler Asteroseismic Science Consortium 1University of Sydney, Australia

Solar-like oscillations have now been measured in dozens of main-sequence and subgiant stars, and in many hundreds of red giants. The oscillation spectra show large numbers of radial and non-radial modes that are excited by near-surface convection. Many of the non-radial modes have mixed character, behaving like p modes in the envelope and like g modes in the core. I will discuss two new results for these mixed modes. The first relates to subgiant stars, where it is well-known that the frequencies of the mixed modes are shifted by avoided crossings. We point out that these avoided crossings betray the presence of g-modes trapped in the core whose frequencies are sensitive diagnostics of the stellar interior. We suggest a new asteroseismic diagram, inspired by the classical C-D diagram, in which the frequencies of the underlying g-modes are plotted against the large separation of the p-modes. This p-g diagram is an instructive way to display results from Kepler (and other studies) and to make a first comparison with theoretical models. The second result relates to red giants. We have discovered gravity-mode period spacings that allow us to distinguish between those red giants burning hydrogen in a shell and the more evolved giants burning helium in the core. Using Kepler photometry, we found many stars whose non-radial modes show multiplets with approximately regular period spacings. These stars fall into two clear groups, allowing us to distinguish unambiguously between hydrogen-burning stars on the red giant branch and helium-burning stars in the red clump and the secondary clump. These results allow new and detailed studies of the properties of red giants in different stages of evolution, including a direct measurement of the mass threshold below which stars undergo a helium flash.

24 Amplitudes of solar-like oscillations: a new scaling relation Tim Bedding1 & Hans Kjeldsen2 1University of Sydney, Australia 2Aarhus University, Denmark

Sixteen years ago, when the first attempts to detect solar-like oscilations were being made, we suggested an empirical scaling relation to predict their amplitudes (Kjeldsen and Bedding 1995). This relation and its various have found widespread use in asteroseismology, despite the fact that observed amplitude of F-type stars such as Procyon are lower than predicted. The flood of data now arriving from the CoRoT and Kepler space missions makes it timely to revisit the amplitude scaling relation. We use simple physical arguments to derive a revised scaling relation, based on the assumption that the power in velocity fluctuations due to p-mode oscillations scales with stellar parameters in the same way as the power in velocity fluctuations due to granulation. The new relation includes a dependance on the mode lifetime and should be testable using observations from CoRoT and Kepler. We also propose a scaling relation for the background power due to granulation, which is also testable.

25 On the relation between the cut-off frequency and the fre- quency of the maximum in the power spectrum in solar-like stars K. Belkacem1, M. J. Goupil2, M. A. Dupret1, R. Samadi2, F. Baudin3, A. Noels1 & B. Mosser2

1Universit´ede Lie`ge,Belgium 2Observatoire de Paris, France 3Institut d’Astrophysique Spatiale, Orsay, France

Asteroseismology of stars that exhibit solar-like oscillations experiences a growing interest with the observational results obtained with the CoRoT and Kepler missions. In this framework, scaling laws between asteroseismic quantities and stellar parameters are becom- ing essential tools to study a rich variety of stars. However, the physical underlying mechanisms of those scaling laws are still poorly known. Our objective is to provide a theoretical understanding of the scaling law between the frequency of the maximum in the power spectrum (νmax) of solar-like oscillations and the cut-off frequency (νc). By using the SoHO-GOLF observations together with theoretical considerations, we first confirm that the maximum of the height or amplitude in the oscillation spectrum is determined by the so-called plateau of the damping rates. The physical origin of the plateau can be traced to the destabilizing effect of the Lagrangian perturbation of entropy in the upper-most layers which becomes important when there is a resonance between the modal period and the local thermal relaxation time-scale.

Based on this analysis, we then find a linear relation between νmax and νc, with a coefficient that depends on the ratio of the Mach number to the third to the mixing-length parameter.

26 Towards a 3-D MHD model of the whole solar interior and its tachocline A. S. Brun1 et al. 1Service d’Astrophysique, CEA CE Saclay, France

We present our latest effort to model in 3-D the nonlinear solar interior magnetohydrodynamics. We use the ASH code to develop a new class of model that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R, thus encompassing part of the nuclear core up to the convection envelope. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior. This is due to the fast angular momentum redistribution in the convective envelope that leads to a fast equator and slow poles, with a conical differential rotation at mid latitude as inverted by helioseismology. Overshooting of the convective motions is also present with an extension of about 0.04R. However the convective meridional circulation is confined to a very small penetration depth and is mostly equatorward at the base of the convection zone. A strict baroclinic balance is found in the tachocline but some departure from it exists in the convective envelope. Internal waves are also excited over the whole radiative interior. When a seed magnetic field is introduced in the convection zone, dynamo action operates efficiently, leading to a magnetic layer in the tachocline dominated by strong axisymmetric toroidal field. If instead a fossil (primordial) magnetic field is introduced in the radiative interior, we find that it connects to the convective envelope transporting the latitudinal shear of the differential rotation via Maxwell stresses with the consequence that Ferraro’s state of iso-rotation if found. This is in contradiction with helioseismic inversion of a solid body rotation of the radiative interior putting the magnetic confinement scenario of the solar tachocline in difficulty.

27 Recent progress and future prospects for inference on solar- type stars Bill Chaplin University of Birmingham, UK

We are entering a golden era for stellar physics, driven by new observations from the space and ground of exceptional quality and scope. In this contribution I shall review recent progress in studies of solar-type stars that these data are making possible, and consider the future prospects (both immediate and more long-term). The biggest breakthrough for these studies has been the NASA Kepler Mission. The asteroseismic survey undertaken by Kepler has met with unprecedented success, yielding detections of solar-like oscillations in around 500 solar-type stars. This represents a dramatic rise, from a pre-Kepler total of about 25, in the number of solar-type stars with oscillations detected. The data present a homogeneous seismic ensemble of unprecedented nature that is large enough to allow statistical studies of intrinsic stellar properties and trends for solar-type stars. I will discuss implications of the asteroseismic estimation of precise and accurate fundamental properties of these stars (i.e., masses, radii and ages) for wider areas of astrophysics. These data, and longer Kepler and CoRoT datasets, are making it possible (and will make it possible) to test the physics at play in stellar interiors. I will discuss various examples, e.g., convection and overshoot in stellar cores (with implications for stellar age calibrations), and internal rotation (with implications for angular momentum histories and the dynamo paradigm for stellar activity). I shall discuss throughout the various demands that the science goals place on dataset lengths and data quality, and how photometric data (space) and Doppler velocity data (ground) may be used in a complementary manner, e.g., to eluciate the physics of the near-surface layers of solar-type stars. The forward look will consider, amongst other topics, prospects for “sounding” stellar activity cycles with Kepler and CoRoT data; the tremendous potential of the high SNR Doppler velocity data that SONG will provide; and, a little further into the future, what PLATO will offer for studies of solar-type stars.

28 The helium cores of extreme horizontal branch stars scruti- nized through g-mode seismology with Kepler and CoRoT St´ephane Charpinet1, V. Van Grootel2, G. Fontaine3, P. Brassard3, E. M. Green4 & S. K. Randall5

1IRAP, Observatoire Midi-Pyr´en´ees,France 2Universit´ede Li`ege,Belgium 3Universit´ede Montr´eal,Canada 4Steward Observatory, University of Arizona, USA 5ESO, Germany

Hot B subdwarf (sdB) pulsators have recently entered the “space age” of asteroseismology, thanks to the CoRoT and Kepler missions. The associated breakthrough in terms of seismic data quality has most notably contributed to unlock the use of the long period (P ∼ 1 − 3 h) g-mode sdB pulsators for probing the internal structure of these stars. Since their discovery in 2003, long period sdB pulsators had remain very difficult to monitor from the ground in order to determine reliably their oscillation frequencies. With CoRoT and Kepler, this difficulty has now disappeared, thus permitting to fully exploit their high asteroseismic potential. In particular, contrary to the p-modes observed in short period (P ∼ 1 − 10 mn) sdB pulsators that were preferentially analysed so far, the g-modes propagate much deeper inside the star, down to the inner core where the thermonuclear fusion of helium is taking place. This property allows us, for the first time, to obtain information on the inner core structure and composition of extreme horizontal branch stars which, by extension, are representative of the helium cores in this intermediate phase of the evolution of low mass stars. I will present the recent results and prospects in this domain.

29 Asteroseismology with the Kepler mission Jørgen Christensen-Dalsgaard Aarhus University, Denmark

The Kepler mission was designed to study extra-solar planetary systems through the transit tech- nique, detecting the presence of planets through the small decrease in stellar brightness as a planet transits the stellar disc. This requires exquisite photometric precision and continuous observations of a very large number of stars, precisely the characteristics needed for asteroseismology using photometry. Furthermore, through asteroseismology it is possible to characterize the central stars in some of the detected planetary systems. This can be used to obtain an accurate determination of the diameter of the star and hence, from the transit depth, the diameter of the planet, as well as to constrain the age of the planetary system. These considerations led to the establisment of the Kepler Asteroseismic Investigation, to explore the asteroseismic potential of the mission. To ensure the optimal use of these unique data we have set up the Kepler Asteroseismic Science Consortium, with now more than 450 members organized in 13 Working Groups each dealing with a specific type of targets. Since its launch in March 2009 Kepler has observed a field of around 100 square degrees in the Cygnus-Lyra region. Most stars, around 150,000, are observed at a cadence of 30 minutes which is sufficient to detect the planetary transits. However, 512 stars are observed at the much faster cadence of 1 minute which is required, for example, to study solar-like oscillations. The selection of these stars can be changed every month, and in the early phase of the mission a survey was carried out to characterize the oscillation properties of a large number of stars. The investigation is now in a phase where selected stars are being followed for extended periods, to increase the frequency resolution and number of frequencies detected. Kepler has produced an overwhelming amount of data on oscillations and other types of variability in a huge number of stars. This includes the characterization of solar-like oscillations of hundreds of stars on or near the main sequence and thousands of red giants, very detailed observations of ’classical’ pulsators such as RR Lyrae stars, and detailed investigations of subdwarf B stars, particularly amongst stars showing relatively long pulsation periods. In addition, the observations have revealed types of variability which have never been seen before and which are still far from being fully understood. Here I provide a brief description of the Kepler mission and the organization of the Kepler As- teroseismic Investigation. In addition, I give a few examples of the very many results that have already been obtained. The work on the data has just started, and there is much more to come!

30 Measurements of solar acoustic waves scattered by sunspots Dean-Yi Chou Physics Department, National Tsing Hua University, Hsinchu, Taiwan

The background solar acoustic waves are scattered by magnetic regions. The scattered waves provide information on the interaction between the magnetic regions and the background waves, and could be a probe for the structure of the magnetic regions. Here we develop a method to measure the scattered wave by a sunspot with helioseismic data. A unidirectional wave is used as the incident wave, which propagates through the sunspot and is scattered by the sunspot. The scattered wave is the difference between the total wave and the incident wave. A method combining the cross-correlation function and deconvolution is used to measure the scattered wave.

31 Stellar differential rotation with depth: the case of the pul- sating pre-white dwarf PG 0122+200 A. H. Corsico´ 1,2, L. G. Althaus1,2, S. D. Kawaler3, M. M. Miller Bertolami1,2 & E. Garc´ıa-Berro4,5

1Facultad de Ciencias Astron´omicas y Geof´ısicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata, Argentina 2Instituto de Astrof´ısica La Plata (CONICET-UNLP) 3Department of Physics and Astronomy, Iowa State University, 12 Physics Hall, Ames, IA 50011, U.S.A. 4Departament de F´ısica Aplicada, Universitat Polit`ecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels, Spain 5Institute for Space Studies of Catalonia, c/Gran Capit`a2–4, Edif. Nexus 104, 08034 Barcelona, Spain

Stellar rotation breaks the spherical symmetry of a star, and in the case of a pulsating star, it removes the intrinsic mode degeneracy of a nonradial g-mode characterized by an harmonic degree ℓ and a radial order k. As a result, each pulsation frequency is split into multiplets of 2ℓ + 1 frequencies specified by different values of the azimuthal index m, with m = 0, ±1,..., ±ℓ. In this work, we explore the potential of asteroseismology to place constraints on the internal rotation of PG 0122+200, the coolest known GW Vir variable star. We employ a dedicated seismological model for this pulsating star in order to assess the expected frequency splittings induced by rotation, and compare them with the observed ones. To this end, we assume different types of plausible internal rotation profiles. This is the so called “forward approach” employed in previous studies. We also employ an inversion method amply used in helioseismology for the inversion of the rotation profile of PG 0122+200. We found strong evidence for differential rotation in this star, being the observed frequency splittings of the rotational multiplets compatible with a rotation profile in which the central regions are spinning more than twice faster than the stellar surface.

32 Constraining the axion mass through the asteroseismology of ZZ Ceti stars A. H. Corsico´ 1,2, L. G. Althaus1,2, A. D. Romero1,2, M. M. Miller Bertolami1,2 & E. Garc´ıa-Berro3,4

1Facultad de Ciencias Astron´omicas y Geof´ısicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata, Argentina 2Instituto de Astrof´ısica La Plata (CONICET-UNLP) 3Departament de F´ısica Aplicada, Universitat Polit`ecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels, Spain 4Institute for Space Studies of Catalonia, c/Gran Capit`a2–4, Edif. Nexus 104, 08034 Barcelona, Spain

White dwarfs constitute the most common end-point of stellar evolution. The relative simplicity of their structure allows one to obtain very detailed models which can be ultimately compared with their observed properties. Pulsating DA (H-rich atmospheres) white dwarfs, also called ZZ Ceti or DAV stars, are the most numerous class of degenerate pulsators, with over 143 members known today. They are characterized by multiperiodic brightness variations caused by spheroidal, non-radial g-modes of low degree with periods between 100 and 1200 s. G117−B15A is the most studied star of this class of variables. The rate of change of its 215.2 s period is very small: P˙ = (4.07 ± 0.61) × 10−15 s/s, with a stability comparable to that of the most stable millisecond pulsars. The rate of change of the period is closely related to its cooling timescale, which can be accurately computed. The axion is a hypothetical elementary particle postulated by the Peccei- Quinn theory in 1977 to solve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a certain range, they are of interest as a possible component of cold dark matter. Interestingly enough, axion emission is supposed to take place in the cores of white dwarfs. Since axions can freely escape from such stars, their existence would increase the cooling rate and, consequently, the rate of change of the periods as compared with the standard one. In this work we present a new asteroseismological model for G117−B15A and we use the observed rate of change of the 215.2 s period to impose constraints on the mass of the axion.

33 Can the interaction of torsional oscillations with a sunspot generate Rossby waves? Sebastien Couvidat W.W. Hansen Experimental Physics Laboratory, Stanford University, USA

Since the seminal study by Charney and Eliassen (1949) of the excitation of Rossby waves on Earth by interaction of mid-latitudes mountain ranges with the westerlies, it has been known that topography can generate a forced response to a zonal flow. Here we study whether a similar response exists at the solar surface when a large-scale zonal flow crosses a sunspot, due to the change in vertical stratification inside this spot. We surmise that this change in stratification is analogous to the change e ncountered by a flow passing over a mountain range on Earth, in that it also changes the absolute vorticity of a fluid column advected by the flow. Following Spruit (2003), we assume that the solar torsional oscillations are a quasi-geostrophic zonal flow, and following Lou (2000) we solve the equations of motion in the shallow-water approximation for the thin photospheric layer. These approximations allow the use of the quasi-geostrophic potential- vorticity equation. Simulations based on this equation show the existence of a forced response to the interaction of torsional oscillations and a sunspot. The fundamental properties of such a response are presented in terms of wavelengths of forced Rossby waves, of their speed, of the building up of a slowly-evolving response downstream of the sunspot, and of the change in these properties as a function of various simulation parameters. Due to the highly simplified framework used, we can only derive an order of magnitude for the amplitude of the response, and exercise due care when interpreting our results.

34 Detailed study of the internal structure of the red-giant star KIC 4351319 observed with Kepler M. P. Di Mauro1 et al. 1INAF - IASF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via del Fosso del Cavaliere 100, 00133 Roma, Italy

We present the results of the asteroseismic analysis of the red-giant star KIC 4351319, observed with the Kepler satellite. The observed oscillation frequencies together with the accurate determination of the atmospheric parameters, provided by additional ground-based spectroscopic observations, enabled us to theo- retically interpret the observed oscillation spectrum. KIC 4351319 appears to oscillate with a well defined solar-type p-modes pattern due to radial acoustic modes and non-radial nearly pure p modes. In addi tion, several non-radial mixed modes have been identified. Theoretical models well reproduce the observed oscillation frequencies and indicate that this star, located at the base of the ascending red-giant branch, is in the hydrogen-shell burning phase, with a mass of ∼ 1.3 M⊙, a radius of ∼ 3.4 R⊙ and an age of ∼ 5.6 Gyr. The main parameters of this star have been determined with an unprecedent level of precision for a red-giant star, with uncertainties of 2 % for mass, 7 % for age, 1 % for radius, and 5 % for luminosity. The excellent observations enabled us also to define the location of the base of the convective enve- lope, and to study additional effects, such turbulent diffusion, overshooting and internal rotation.

35 Time-distance analysis of deep solar convection T. L. Duvall1, Jr. & S. M. Hanasoge2 1NASA Goddard Space Flight Center, USA 2Max-Planck-Institut f¨urSonnensystemforschung, Germany

Recently it was shown by Hanasoge, Duvall, and DeRosa (2010) that the upper limit to convective flows for spherical harmonic degrees l

36 The physics of pulsating white dwarf stars G. Fontaine & P. Brassard D´epartement de Physique, Universit´ede Montr´eal,Succ. Centre-Ville, C.P. 6128, Montr´eal,QC H3C 3J7, Canada

We present a brief summary of the connection between white dwarf physics and the asteroseis- mological inferences that have been made so far on such stars. Currently, there are four known distinct families of pulsating white dwarfs, with the possibility of a fifth type that needs to be confirmed. The well-established classes are 1) the GW Vir stars (He/C/O-atmosphere stars with Teff ∼ 120,000 K), 2) the V777 Her stars (He-atmosphere, Teff ∼ 25,000 K), 3) the ZZ Ceti stars (H-atmosphere, Teff ∼ 12,000 K), and 4) the recently discovered Hot DQ pulsators (C-atmosphere white dwarfs, with Teff ∼ 20,000 K). These pulsators all show multiperiodic luminosity variations caused by low-degree and low- to intermediate-order g-mode instabilities. The classic κ-mechanism is at work in the GW Vir stars, while convective driving provides most of the excitation in the other three types of white dwarf pulsators. Among other results, we discuss some recent interest- ing developments on the mapping of the internal rotation profiles of white dwarfs on the basis of asteroseismology.

37 Fast rotating solar-like stars from the first year of Kepler observations R. A. Garc´ıa1, M. J. Thompson2, T. S. Metcalfe2 and PE11 Team of WG#1. 1Service d’Astrophysique, CEA CE Saclay, France 2High Altitude Observatory, USA

The NASA Kepler mission is providing an unprecedented set of asteroseismic data. In particular, short cadence lightcurves, of ∼ 60 s samplings, allow us to study solar-like stars covering a wide range of masses, spectral types and evolutionary stages. From around 2000 stars observed for a month long during the survey phase of this mission, oscillations have been observed in around 600. The measured light curves can present features related to the surface magnetic activity (starspots) and thus, we are able to obtain a good estimation of the surface (differential) rotation. In this talk we will show the first results done by the PE11 Team of the solar-like working group (WG#1), on the distribution of the rotation in this sample of pulsating stars, and we will compare it with some proxies of surface activity and the amplitude of the measured pulsations (Amax). We will concentrate only on fast rotators, spinning with periods of 10 days, because our light series are limited to one-month long.

38 Adjoint tomography of the Sun S. M. Hanasoge1, A. C. Birch2, L. Gizon1† & J. Tromp3 1Max-Planck-Institut f¨urSonnensystemforschung, Germany 2A Division of NorthWest Research Associates, Inc., USA 3Princeton University, USA

We describe a general theory to attempt inverse problems in local helioseismology. This method allows for the computation of kernels around arbitrary background models, rendering non-linear inverse problems tractable. The adjoint method is a form of constrained partial differential equa- tion optimization that describes a means of extracting derivatives of a misfit function to model parameters. Thus, given a misfit function such as the L2 norm of the difference between observed and predicted helioseismic travel times, the gradient describes the manner in which one can alter the properties of the underlying medium to march towards a misfit minimum. The method relies on the numerical computation of a series of wave fields that are driven by two types of sources, the average wave-excitation spectrum, resulting in the forward wavefield and the difference between predictions and observations, resulting in an adjoint wavefield. Sensitivity kernels emerge directly from the evaluation of an interaction integral involving these wavefields.

†presenter

39 Theoretical instability domains in the upper part of the HR diagram M. Godart1 et al. 1University of Li`ege,Belgium

Massive stars are characterized by a large radiation over gas pressure ratio and a large temperature over density ratio. With increasing stellar initial mass, they suffer stronger stellar winds which play an important role in the chemical enrichment of the galaxies. The induced mass loss also affects the evolution and internal structure of massive stars on the main sequence (MS) and on the post- main sequence phase (post-MS). Recent ground-based observations and space missions have shown the presence of pulsations in massive stars, such as accouctic and gravity modes excited by the κ- mechanism and even solar-like oscillations. Strange modes could also be excited in the most massive stars. κ-mechanism instability domains are presented for the upper HR diagram (up to 70M⊙) on the MS and on the post-MS. We compute evolutionary tracks and non-adiabatic frequencies for different input parameters such as the metallicity, the mass loss rate and the overshooting parameter.

40 Physics of the Sun gleaned from helioseismology Douglas Gough University of Cambridge, UK

Now that we are entering a wonderful new era in which an enormous amount of seismic information from a wide variety of stars is being gathered, it is useful to take stock of the helioseimological inferences that we have drawn, and remind ourselves of what we have really learned about the structure of the Sun and what we can infer from that about the physics of solar and stellar evolu- tion. There are some properties of the Sun which we believe are well established; others are more uncertain because they depend upon circumstantial evidence or, more dangerously, unsubstan- tiated, and sometimes forgotten, assumptions. Notwithstanding Eddington’s comparison of the inside of a star to that of the Earth, the Sun and other sun-like stars are actually very complicated dynamical systems. The precise manner in which they have evolved to their present states is not securely known. In trying to establish their properties we have made many simplifying assump- tions, from which we have developed a picture which more-or-less corresponds to the observations we have in hand. But as observations become more and more precise, and in consequence, at least conceptually, more and more extensive, as in many other domains of enquiry, we become more and more aware of what we do not know. One thing that we must bear in mind, however, is that by and large the seismic waves that we use for diagnosis are described by very simply physics, and therefore, granted that their manifestation as surface disturbances has been interpreted correctly, and that the analyses of their properties have been correctly and logically performed, the inferences that we can validly draw can hardly be doubted; it goes without saying that it is important for us all to be acutely aware of what can and cannot be validly inferred from seismology when trying to assess the plausibility of the claims that are made from the analyses. It is then our duty to be explicit about what additional assumptions we are making when bringing those inferences to bear on aspects of physics. Very briefly I shall touch on the methods that are used to infer aspects of the hydrostatic structure and macroscopic flow that have been addressed by helioseismology: so-called inversions that lead to seismic representations, and seismic calibrations of theoretical models. The first necessarily require supplementary information, or assumption, to address any aspect of physics; the second have such information incorporated at the outset. Both have their complementary uses, and to- gether have enabled us to address, although not necessarily resolve, issues of chemical abundance, equation of state, neutrino production, angular-momentum transport, and even magnetohydrody- namical phenomena. With helioseismology we have made enormous progress in heliophysics. With asteroseismology we shall do likewise in asterophysics.

41 Impact of rotation on seismic models for 2 COROT stars HD49933 and HD181420 Marie-Jo Goupil Observatoire de Paris, France

I will present the impact of taking into account rotation at several levels —in the stellar model through rotationally induced mixing and through the effect of rotation on the oscillations— on the seismic models obtained for 2 COROT stars HD49933 and HD181420.

42 The new solar chemical composition Nicolas Grevesse Centre Spatial de Li`egeand Institut d’Astrophysique et de G´eophysique,Universit´ede Li`ege,Bel- gium

With Martin Asplund (Max Planck Institute for Astrophysics, Garching, Germany), Jacques Sauval (Observatoire Royal de Belgique, Brussels, Belgium) and Pat Scott (Stockholm Univer- sity, Sweden, now at McGill University, Canada) we have recently re-determined the abundances of nearly all the available chemical elements in the solar photosphere, from Lithium to Thorium. The new data are compared with all the available data in a review that was published in Annual Review of Astronomy and Astrophysics (47, 481-522, 2009). This new complete and homogeneous analysis results from:

• a very careful selection of spectral lines of all the indicators of the abundances present in the solar photospheric spectrum and discussion of the atomic and molecular data, • an analysis of these lines based on a new 3D model of the solar outer layers taking non-LTE effects into account when possible.

We shall present these new results, compare them with other recent solar data as well as with recent results for the solar neighbourhood and discuss some of their most important implications in solar as well as in stellar physics.

43 Dark matter and its effects on helioseismology Ryan Hamerly & Alexander Kosovichev Stanford University, USA

Helioseismology can be used to place new constraints on the properties of dark matter, allowing solar observations to complement more conventional dark matter searches currently in operation. During the course of its lifetime, the Sun accretes a sizeable amount of dark matter. This accreted matter affects the heat transport of the stellar core in ways that helioseismology can detect, or at least constrain. We modify the CESAM stellar evolution code to take account of dark matter, determine the effect of light WIMP models on the stellar structure, and compare this to current helioseismology data.

44 Hybrid pulsators among A and F stars G. Handler Nicolaus Copernicus Astronomical Center, Poland

Four classes of pulsating stars occupy the intersection between the lower instability strip and the main sequence: Delta Scuti stars, rapidly oscillating Ap stars, Gamma Doradus stars and solar like oscillators. Until recently, stars that have pulsations of more than one of these types excited, where considered unusual; some of the oscillations were even suspected of being mutually exclusive. Results from the asteroseismic part of the Kepler mission have completely destroyed this picture. Hybrid Delta Scuti/Gamma Doradus stars appear to be the rule rather than the exception, and there are Ap stars pulsating in modes that characterize Gamma Doradus and Delta Scuti stars. In addition, there are intriguing cases of a roAp/Gamma Doradus hybrid, and of a Delta Scuti star that also shows solar-like oscillations. I present an overview of these findings and discuss what we might learn from them.

45 Characterisation of red-giant stars in the public Kepler data S. Hekker1 et al. 1Astronomical Institute, University of Amsterdam, The Netherlands

The first public release (about 150 000 stars) of long-cadence stellar photometric data collected by the NASA Kepler mission has now been made available. Here we present a characterisation of the red-giant (G-K) stars in this large sample in terms of their solar-like oscillations. Just over 70%, i.e., 11,805 out of the 16,511 red giants in the sample show detectable solar-like oscil- lations, and from these oscillations we are able to estimate the fundamental properties of the stars. This asteroseismic analysis reveals different populations: low-luminosity H-shell burning red-giant branch stars, cool high-luminosity red giants on the red-giant branch and He-core burning clump and secondary-clump giants. Furthermore, we found that the detection of solar-like oscillations in red giants does not depend on the long-term variability, i.e. variability not associated with the oscillations, but from for instance activity and granulation.

46 Asteroseismic inferences on red giants in open clusters NGC 6791, NGC 6819 and NGC 6811 using Kepler S. Hekker1 et al. 1Astronomical Institute, University of Amsterdam, The Netherlands

Four open clusters are present in the Kepler field of view and timeseries of nearly a year in length are now available. These timeseries allow us to derive asteroseismic global oscillation parameters of red-giant stars in the three open clusters NGC 6791, NGC 6819 and NGC 6811. From these parameters and effective temperatures, we derive mass, radii and luminosities for the clusters as well as field red giants. These parameters allowed us to study the influence of evolution and metallicity on the observed red-giant populations.

We find that the mass has significant influence on the asteroseismic quantities ∆ν vs. νmax relation, while the influence of metallicity is negligible, under the assumption that the metallicity does not affect the excitation / damping of the oscillations. The positions of the stars in the H-R diagram depend on both mass and metallicity. Furthermore, the stellar masses derived for the field stars are bracketed by those of the cluster stars. We also find that both the mass and metallicity contribute to the observed difference in locations in the H-R diagram of the old metal-rich cluster NGC 6791 and the middle-aged solar-metallicity cluster NGC 6819. For the young cluster NGC 6811, the explanation of the position of the stars in the H-R diagram challenges the assumption of solar metallicity, and this open cluster might have significantly lower metallicity [Fe/H] in the range −0.3 to −0.7 dex. Also, nearly all the observed field stars seem to be older than NGC 6811 and younger than NGC 6791.

47 Helioseismic observations of solar convection zone dynamics and their relationship to solar activity Frank Hill, Rudi Komm, Irene Gonzalez´ Hernandez´ , Rachel Howe, Shukur Kholikov & John Leibacher National Solar Observatory, USA

The bulk flows in the solar interior play an important role in the dynamo mechanism of the the solar activity cycle, and also affect active region evolution. The dynamics have been inferred using both global and local helioseismology applied to data from the Global Oscillation Network Group (GONG), the Michelson Doppler Imager (MDI) on board SOHO, and the Helioseismic and Magnetic Imager (HMI) on SDO. The global analysis has revealed temporal variations of the torsional oscillation zonal flow as a function of depth that may be related to the properties of the solar cycle. The horizontal flow field as a function of heliographic position and depth can be derived from ring diagrams, and shows near-surface meridional flows that change over the activity cycle. Time-distance techniques can be used to infer the deep meridional flow, which is important for flux-transport dynamo models. The horizontal velocity measurements can be transformed into divergence and vorticity fields using the continuity equation and a model of the solar density as a function of depth. Temporal variations of the divergence and vorticity can be used to search for emerging active regions, and to understand the production of flare activity. This presentation will summarize the state of our knowledge in these areas.

48 Driving mechanisms of stellar pulsations G¨unter Houdek Institute of Astronomy, University of Vienna, Austria

I shall present an overview of our current understanding of pulsation mode driving in various type of pulsating stars. It will include classical pulsators, such as delta Scuti, gamma Doradus and roAp stars, and main-sequence stars in which the oscillations are excited by turbulent convection. Emphasis will also be given on the role of modelling convection and mode stability, for example, on the location of the classical instability strip. Theoretical results will be compared with some of the latest Kepler and ground-based observations.

49 Radiative levitation in subdwarf B stars Haili Hu1, Evert Glebbeek2, Christopher Tout1 & Marc-Antoine Dupret3 1Institute of Astronomy, University of Cambridge, United Kingdom 2Department of Physics & Astronomy, McMaster University, Hamilton, Canada 3Institut d’Astrophysique et de G´eophysiquede l’Universit de Li`ege,Belgium

Pulsations in subdwarf B stars are attributed to radiative levitation of iron-group elements in the stellar envelope. Previous models approximate the effects of radiative levitation by either assuming a diffusive equilibrium profile in a static stellar model (Charpinet et al. 1997), or by parametrically enhancing the iron during the evolution (Hu et al. 2008). Although these models have been successfully used for seismology of sdB stars, there are still some discrepancies that remain to be resolved. For example, observations show that only 10% of the sdB stars in the p-mode instability strip pulsate, while the models predict that pulsational instability is reached within 0.1% of the EHB evolutionary time. Evidently, radiative levitation is not as efficient as in the equilibrium models, that neglect competing processes such as turbulence and stellar winds. Also, the theoretical blue-edge of the g-mode instability strip is not entirely consistent with the observed blue-edge. It has been proposed that including diffusion of other elements besides iron could (at least partly) solve this problem (see Jeffery & Saio 2006 and Hu et al. 2009). It is clear that stellar evolution models with time-dependent atomic diffusion, as we compute here, are necessary to address the above problems. We perform detailed calculations of radiative acceler- ations using atomic data from the Opacity Project. The diffusion velocities are obtained by solving Burgers’ diffusion equations with the algorithm developed by Thoul et al. (1994) and updated by Hu et al. (2010). Atomic diffusion is then included during the evolution of a typical subdwarf B star, which we follow with the STARS stellar evolution code (Eggleton 1971). STARS solves the equations of stellar structure and chemical composition simultaneously and implicitly. We show that this unique approach provides a more numerically stable method of including radiative levi- tation than other non-simultaneous approaches. Finally, we investigate the effects of weak stellar winds and turbulent mixing of the surface layers on the stability of the pulsation modes during the EHB evolution. This gives a new way to constrain these processes, and we compare our preliminary results with previous, independent studies.

50 First magnetic field models for recently discovered magnetic beta Cephei and slowly pulsating B stars S. Hubrig1 et al. 1Astrophysical Institute Potsdam, Germany

In the last years we have acquired numerous low resolution spectropolarimetric observations for a sample of beta Cephei, Slowly Pulsating B, and normal B-type stars. Roughly one third of the studied beta Cephei stars have detected magnetic fields, and the fraction of magnetic Slowly Pulsating B stars ist even higher, up to 50%. Our comparative study between samples of B- type pulsating stars and a sample of well-studied Bp stars with known periods and magnetic field strengths indicate that longitudinal magnetic fields in pulsating stars are weaker than those of Bp stars, suggesting that the magnetic field strength is an important factor for B type stars to become chemically peculiar. The strongest magnetic fields appear in young Bp stars, hinting at a magnetic field decay in stars at advanced ages. In spite of detections of magnetic fields in a number of pulsating B-type stars, their impact on stellar rotation, pulsations, and element diffusion has not yet been sufficiently studied. One of the reasons for this is the lack of knowledge about their rotation periods, the magnetic field strength distribution and temporal variability, and the field geometry. Using our most recent low resolution FORS2 and high resolution SOFIN longitudinal magnetic field measurements, we were able to determine rotation periods and constrain the field geometry of two beta Cephei stars, one candidate beta Cephei star, and one Slowly Pulsating B star.

51 The roAp star with the strongest magnetic field: the charac- terization of HD 154708 S. Hubrig1 et al. 1Astrophysical Institute Potsdam, Germany

The cool roAp star HD 154708 with a pulsations period of 8 minutes possesses the strongest mag- netic field among the roAp stars. A longitudinal magnetic field of up to 8 kG and a mean magnetic field modulus of about 24.5 kG were measured using the FORS1 and UVES instruments installed at one of the 8-m VLT telescopes. The magnetic field of HD 154708 is so strong that a number of spectral lines are distorted beyond recognition by the partial Paschen-Back effect. The radial velocity amplitudes in the rare earth element lines were found unusually low, suggesting that roAp stars with stronger magnetic fields have lower pulsation amplitudes. In our presentation we will discuss the major characteristics of this remarkable star in comparison to those of cool Ap stars occupying the roAp instability strip.

52 First detection of a magnetic field in the fast rotating pulsator ζ Ophiuchi S. Hubrig1, L. M. Oskinova2, & M. Scholler¨ 3 1Astrophysikalisches Institut Potsdam, Germany 2Universit¨atPotsdam, Institut f¨urPhysik und Astronomie, Germany 3European Southern Observatory, Germany

The massive O-type star ζ Ophiuchi is remarkable by its almost break-up rotation with v sin i = 400 km s−1, strong variability in various wavelength domains, peculiar nitrogen abundance, and runaway characterictics. Highly precise MOST (Microvariability and Oscillations of Stars) satellite photometry in 2004 has yielded at least a dozen significant oscillation frequencies between 1 and 10 cycles/day, hinting at a behaviour similar to β Cephei-type stars (Walker et al. 2005, ApJ 623, L145). It was suggested that ζ Oph gained its velocity in a supernova explosion within a close binary in the Upper Scorpius association about 1–2 Myr ago. Using FORS 2 spectropolarimetric observations of ζ Oph, we recently achieved the first detection of a magnetic field in this remarkable star.

53 Detecting subsurface signatures of emerging solar active re- gions Stathis Ilonidis & Junwei Zhao W.W.Hansen Experimental Physics Laboratory, Stanford University, U.S.A.

It is widely believed that solar magnetic fields are generated by a dynamo action in the interior of the Sun and then emerge to the surface. The properties of flux emergence are related to some of the most important problems in solar and stellar physics: the depth of dynamo, the appearance and evolution of active regions, the formation of sunspots, the initiation of flares and coronal mass ejections, and the 11 year activity cycle. We develop a new helioseismic measurement scheme, based on time-distance technique, and demonstrate that it is capable of detecting signatures of emerging magnetic flux in the solar interior before the flux becomes visible on the surface. We apply this technique to continuous Doppler observations of the Sun by both SOHO/MDI (Michelson Doppler Imager onboard Solar and Heliospheric Observatory) and SDO/HMI (Helioseismic and Magnetic Imager onboard Solar Dynamics Observatory). Our measurement scheme is applied only to quiet regions, before the emerging magnetic flux appears in these regions, in order to avoid surface magnetism effects. In several events, we have detected surprisingly strong acoustic travel-time variations of the order of 10-20 seconds. Such variations are always detected 20-25 hours before high peaks in the photospheric magnetic flux rate. The detected travel-time anomalies are as deep as ∼ 65, 000 km, setting a low threshold for the depth of the dynamo inside the Sun. The technique and the results of this work improve our understanding of solar magnetism, provide a new platform for further studies of magnetism in the Sun’s interior, and greatly benefit space weather forecast.

54 Traditional approximation for low-frequency modes in rotat- ing stars Hiroyuki Ishimatsu, Tomoko Oturu & Hiromoto Shibahashi Department of Astronomy, University of Tokyo, Tokyo, Japan

Traditional approximation, in which the Coriolis force associated with radial motion and the radial component of the Coriolis force associated with horizontal motion, is reasonably good for very low frequency modes, in which the horizontal motion dominates the oscillation. In this approximation, the angular dependence of eigenfunction is expressed in terms of the Hough functions, and the radial dependence is expressed in a form similar to the case of non-rotating stars. By solving numerically the equations governing the angular dependence and the radial dependence of eigenfunctions, we demonstrate that the temperature perturbation near the surface is large enough to produce detectably large luminosity variation while the kinetic energy of modes is confined mainly near the stellar core. We discuss the possibility of manifestations of these modes in real stars.

55 Asteroseismology and chemical stratification in hot sub-dwarfs: the remarkable case of the zirconium star LS IV−14◦116 C. Simon Jeffery & Naslim, N. Armagh Observatory, College Hill, Armagh BT61 9DG, Northern Ireland, UK

Hot subdwarfs are low-mass core-helium burning stars. They form either after a red giant has its hydrogen-envelope stripped away or following the merger of two white dwarfs. Both processes should produce a star with a high helium surface abundance, yet only about 10% of hot subdwarfs are helium-rich (> 10% by number). The vast majority have helium-poor atmospheres, where it is believed that radiatively-driven diffusion causes hydrogen to float above the helium. The rˆole of opacity is further emphasized by substantial overabundances of several high-Z elements. In contrast, iron and nickel appear to sink out of the atmosphere and accumulate at a temperature where their specific opacity is highest and where, under appropriate conditions, they can drive pulsations. Clearly, radiative processes are crucial in forming the internal chemical structure of hot subdwarfs. Asteroseismology is a natural tool for exploring this stratification. A key question posed by hot subdwarfs with significant quantities of helium in their photosphere is: “Do different surface chemistries represent distinct groups of stars with different evolutionary ori- gins, or do they represent groups of stars at different stages along similar evolutionary sequences?” One corollary is whether we are observing hot subdwarfs in transition from having helium rich sur- faces, to having helium poor surfaces, as the relatively slow radiatively driven diffusion “sorts” the surface chemistry. Another is how well we understand the physics of time-dependent radiatively- driven diffusion in stellar surface layers. We report the recent discovery of a 4 dex excess of zirconium, strontium, and yttrium in the photosphere of the moderately helium-rich subdwarf LS IV−14◦116. Together with germanium, these elements probably form thin radiatively-supported cloud layers in the photosphere. It is proposed that these clouds will only survive for a ≤ 105 years), at a unique temperature and luminosity, as the star contracts towards the extended horizontal branch. Two other hot subdwarfs with very exotic chemistries support this hypothesis. LS IV−14◦116 is the only known pulsating helium-rich subdwarf (He-sdBV). Its periods (0.5 – 1.5 hrs) are too long to be p-modes. Its effective temperature is too high to allow g-modes. Consequently the driving mechanism is not understood at all. Could the extraordinary chemistry help to explain the pulsations? Is there a link with the roAP stars, or with the Bp(He) stars? Does a magnetic field play any rˆole?Can asteroseismology shed new light on the physics of radiatively- driven diffusion?

56 epsilon Ophiuchi - revisiting a red giant Thomas Kallinger1 and the MOST Science Team 1University of British Columbia, Canada

In only a decade, seismology of red giant stars has grown from infancy to adulthood in the study of stellar structure and evolution. The stimulants for this accelerated growth have been light curves from space, first provided by the WIRE startracker and MOST, and continuing with CoRoT and Kepler. The latter two missions have detected solar-like oscillations in thousands of cool giants. However, almost all of the stars in this impressive sample are faint, with little known about their basic properties. Even reliable spectral classifications are lacking for many of them. MOST is the only spacebased photometer capable of continuous observations of bright stars (chosen from a very broad region of the sky, and with time coverage up to two months) for which we have independent constraints (e.g., spectroscopy, interferometry) which can be essential to extract detailed internal structure from the stars’ p-modes. After the pioneering MOST photometry of the G9 giant ε Ophiuchi in 2003, the observed eigen- spectrum allowed two interpretations: only long-lived radial modes (believed at that time to be true for all pulsating red giants) or a mix of radial and non-radial modes with short lifetimes. The controversial claim of excitation of non-radial modes in red giants was later confirmed by CoRoT and Kepler. But the ambiguity remained for ε Oph: Only radial modes, or a mix of radial and non-radial? To answer that question, another month of MOST observing was dedicated to the star in 2010. The new data, combined with the original time series, prove the presence of non-radial modes in this red giant. This confirms that ε Oph —for which the extensive groundbased observations, in combination with seismology, make it a superb laboratory to test structure and evolution— is not a maverick among the homogeneous group of pulsating red giants.

57 Development of the fiber-link between Okayama 1.88 m tele- scope and high dispersion echelle spectrograph, HIDES Eiji Kambe Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Honjyo 3037- 5, Kamogata, Asakuchi, Okayama 719-0232, Japan

Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan is lo- cated at the western part of Honshu island in Japan. Being at the eastern longitude in the northern hemisphere, it is a relatively unique astronomical observing site around the globe. We have a 1.88 m telescope, which is the largest among research-purposed optical telescopes in Japan, and the HIgh Dispersion Echelle Spectrograph, HIDES. The HIDES was completed in 1999 and continuously upgraded since then; we installed an iodine cell for precise radial velocity measurement in late 2000 and three mosaic CCDs in late 2007. With these instruments, we occasionally attend to and/or organize multi-site campaigns on asteroseismological targets. In 2007 we started developing a fiber-link from the Cassegrain focus of the 1.88 m telescope to the entrance of HIDES, aiming at improving efficiency of observation by one magnitude as well as its radial velocity measurement precision. The optical fiber always leads the stellar light within FOV of 2.7 arc-second to the HIDES, while the typical seeing size at OAO is 1.5 arc-second. We introduce an image slicer at the entrance of the HIDES not to degrade the resolution of spectrum for such large FOV. We had its first-light on December 2009, and have made commissioning observations throughout 2010. From the observations, we have confirmed that the throughput with the new fiber system is practically better by one magnitude (at around 550 nm) compared to that with the conventional slit. The radial velocity precision also improves at least in short-term observations, reaching as close as 1 m s−1 in some cases. I will report on such preliminary results of our commissioning observations in my talk. Lastly, I will introduce a bit more on the Okayama Astrophysical Observatory (facilities, weather statistics, etc.), hoping for more extensive collaborations on asteroseismological observations in near future.

58 Pulsating white dwarfs in globular clusters A. Kanaan, A. Zabot & L. Fraga Universidade Federal de Santa Catarina, Brazil

We present our current efforts to detect pulsating white dwarfs in globular clusters and analyze the future of this area when ELT, GMT and TMT come on line. The white dwarf pulsation community has been working on the group properties of DAVs, DBVs and DOVs for a long time, DAVs are the most numerous group and consequently, those whose properties are best known. The known DAVs are field stars, therefore they belong to totally unrelated progenitors. Seismology of pulsating white dwarfs in nearby globular clusters can provide us with homegenous groups of white dwarfs, coming from very similar ancestors. This is impossible to be achieved in any other way and will bring us hundreds of new objects; members of the same cluster all sharing a common origin. We have recently been granted four hours on Subaru Suprime-CAM to try and detect pulsating white dwarfs in M4. We expect to find more than 10 pulsating white dwarfs in M4 with only these four hours. Longer observations should reveal hundreds of such stars. Today we may able to detect pulsating white dwarfs in M4 and NGC 6397, when ELT comes on line we should be able to improve the quality of data on the nearby clusters and push the limit to at least 3 magnitudes farther, up to NGC 6626, increasing the number of observable clusters from 2 to 20.

59 The ZZ Ceti instability strip and magnetic white dwarfs in the SDSS S. O. Kepler1, B. G. Castanheira2, S. J. Kleinman3, Detlev Koester4 & Atsuko Nitta3 1Instituto de F´ısica da UFRGS, Brazil 2Institut f¨urAstronomie, Wien, Austria 3Gemini Observatory, Hawaii, USA 4Institut f¨urTheoretische Physik und Astrophysik, Universit¨atKiel, Kiel, Germany

Using the SOAR 4.1 m telescope over the last 6 years, we discovered over 60 new ZZ Ceti pulsators, including low amplitude pulsations for five stars previously reported as Not–Observed–to–Vary (NOV) inside the ZZ Ceti instability strip. Since we have discovered low amplitude pulsations in every NOV inside the instability strip we have observed down to a detection limit around 1 mma, the observational evidence indicates a pure ZZ Ceti instability strip. In our searches, we also lowered the detection limit for ten NOVs near the edges of the ZZ Ceti instability strip. Our goal is the determination of the boundaries in Teff and log g of the instability strip and the seismological study of the variables. We also report on our detection of Zeeman splittings in more than 800 white dwarf stars, when classifying by eye more than 24 000 spectra selected as possible white dwarf stars from the Sloan Digital Sky Survey Data Release 7. Our field estimations range from 90 MG to about 1 MG. These magnetic white dwarf stars cover the whole range of temperature and spectral classes observed. As the Zeeman splittings broadens the lines, we cannot use the line profiles to estimate surface gravity directly. We therefore excluded the magnetic white dwarfs from our average mass estimate 〈 〉 ± 〈 〉 ± of normal DAs and DBs, M DA = 0.604 0.003M⊙ and M DB = 0.646 0.006M⊙. The mean masses for DAs and DBs are different.

60 Asteroseismology of rich pulsating white dwarfs A. Bischoff-Kim1 & T. S. Metcalfe2 1Georgia College & State University, Department of Chemistry, Physics and Astronomy,CBX 082, Milledgeville, GA 31061-0490, USA 2High Altitude Observatory, National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307-3000, USA

White dwarfs are the end product of the evolution of around 98% of the stars. Buried in their interiors are the records of physical processes that take place during earlier stages in the life of the star. Nuclear reaction rates during the core helium burning phase set the core composition of white dwarfs, while the relative time spent burning hydrogen and helium during the AGB phase and massloss episodes determine the thickness of the helium layer. Based on these physical processes and subsequent diffusion in stellar interiors, stellar evolution calculations make specific predictions about what the internal chemical structure of white dwarfs should be. White dwarf asteroseismology provides a powerful test of these predictions. Pulsating white dwarfs fall in three instability strips; from hot to cool the DOV’s, DBV’s and DAV’s. As white dwarfs cool, they reach nearly fully degenerate conditions and essentially stop contracting. Meanwhile, chemical diffusion of the elements create a differentiated interior. DBV’s and DAV’s in particular are relatively simple to model, as gravitational contraction is minimal in these stars. DAV’s are expected to have fully differentiated stellar interiors. White dwarfs pulsate through non-radial g-mode oscillations with periods varying between 200 and 1500 seconds. Asteroseismology of these stars reveals the location of any internal chemical transitions zones and potentially the “shape” of these transition zones. The best targets to test the predictions of stellar evolution with asteroseismology are DAV’s and DBV’s that exhibit a dozen or more pulsation modes. These rich white dwarf pulsators provide both a challenge to asteroseismic analyses and an opportunity to probe the chemical structure of white dwarf interiors in greater detail. We present some results of such analyses for DBV EC20058 and DAV EC14012. The latter is a particularly rich white dwarf pulsator with 20 modes, 10 of which are potentially ℓ = 1 consecutive modes.

61 Mechanism of acoustic waves excitation by turbulent convec- tion and vortex dynamics Irina N. Kitiashvili1, A. G. Kosovichev1, N. N. Mansour2 & A. A. Wray2 1Stanford University, USA 2NASA Ames Research Center, USA

The problem of excitation of acoustic waves by turbulent convection is one of the key questions in solar and stellar physics. We present new results of 3D radiative hydrodynamic simulations of the solar convection zone that reveal a strong connection between the wave excitation events and dynamics of vortex tubes, which are located mostly in the intergranular lanes. These whirlpool- like flows are characterized by very strong horizontal shear velocities (7–11 km/s) and downflows (∼ 7 km/s), and are accompanied by sharp decreases of temperature, density and pressure at the surface. High-speed whirlpool flows can attract and capture other vortices. The simulations show that strong acoustic events are generated by a process of annihilation of vortex tubes. We investigate properties of the turbulent acoustic sources and the waves propagating in the upper convection zone.

62 Self-organization of solar turbulent convection in magnetic field Irina N. Kitiashvili1, A. G. Kosovichev1, N. N. Mansour2 & A. A. Wray2 1Stanford University, USA 2NASA Ames Research Center, USA

Observations of the solar surface show highly turbulent behavior of convection, which in presence of magnetic field leads to the formation of organized, coherent magnetic structures. We present results of realistic 3D MHD simulations of the solar surface and subsurface layers, which demonstrate the physical properties of magnetoconvection for various topology and strength of magnetic field. In particular, in strongly inclined almost horizontal magnetic field regions, the turbulent magnetocon- vection forms long filamentary magnetic structures with a strong subsurface shear flow, providing a mechanism of the Evershed effect observed in sunspot penumbrae. In region with an initially uniform vertical magnetic field the magnetoconvection may lead to a spontaneous formation of compact self-organized structures with strong concentrations of magnetic field. These structures have characteristics of solar pores. A critical role in the formation of magnetic structures is played by turbulent vorticity. The simulation results explain a number of phenomena, observed by Hinode and SDO/HMI, and make predictions of the subsurface dynamics of magnetic regions, which can be verified by local helioseismology.

63 Radiative hydrodynamics simulations of turbulent convection for Kepler target stars Irina N. Kitiashvili1, J. A. Guzik2, A. G. Kosovichev1, N. N. Mansour3, H. Saio4, H. Shibahashi5 & A. A. Wray3 1Stanford University, USA 2Los Alamos National Laboratory, USA 3NASA Ames Research Center, USA 4Tohoku University, Japan 5University of Tokyo, Japan

The solar-type pulsators are characterized by acoustic oscillation modes excited by turbulent granu- lar convection in the upper convective boundary layer. As the stellar mass increases the convection zone shrinks, the scale and intensity of the turbulent motions increases, providing more energy for excitation of acoustic modes. When the stellar mass reaches about 1.6 solar masses the upper con- vection zone consists of two very thin layers corresponding to H and He ionization, and in addition to the acoustic modes the stars show strong internal gravity modes. The thin convection zone is often considered insignificant for the stellar dynamics and variability. We use 3D numerical ra- diative hydrodynamics simulations to study convective and oscillation properties of main sequence stars from the solar-type stars to more massive stars. We presents the simulations results for some of the target stars selected for the Kepler GO project “Transition in variable stars: from solar-type stars to gamma-Doradus stars”. For the moderate-mass (A-type) stars the simulations reveal su- personic granular-type convection of the scale significantly larger than the solar granulation, and strong overshooting plumes penetrating into the stable radiative zone, that can affect oscillation properties of these stars.

64 Pulsation convection modeling of the DAV white dwarf star, G29-38, in different states M. H. Montgomery & S. J. Kleinman2‡ 1University of Texas at Austin, USA 2Gemini Observatory, USA

Pulsations in white dwarf stars have long been viewed as probes of their star’s internal structure and composition. Recently, we have begun a project to empirically measure and paramaterize con- vection in pulsating white dwarf stars through light curve analysis. We are able to exploit the non- linearities in the observed light-curves to derive a functional form of the thermal response timescale of the convection zone. This technique requires high-quality data sets and well-understood pulsa- tion spectra, so its application is limited to stars with such data. One star, G29-38, a DAV, has been observed extensively enough both by the Whole Earth Telescope and single site campaigns that there are multiple data sets suitable for analysis. Furthermore, G29-38 has been observed to change its pulsation behavior from one observing season to another. Here, we compare the results of our convective modeling and stellar parameter determinations with two different data sets from distinctly different pulsation states.

‡presenter

65 The solar rotation and its evolution during cycle 23 S. G. Korzennik1 & A. Eff-Darwich2 1Harvard-Smithsonian Center for Astrophysics, USA 2Instituto de Astrof´ısica de Canarias, Spain

We present the most exhaustive and accurate inferences of the internal solar rotation rate and its evolution during solar cycle 23. A full solar cycle of MDI observations have been analyzed using our state of the art fitting methodology. Time series of various lengths have been fitted, from a single 4608-day long epoch (64 times 72 day or 12.6 yr) down to 64 separate segments for the “traditional” 72-day long epochs. We used time series of spherical harmonic coefficients computed by the MDI group but using an improved spatial decomposition. This decomposition now includes our best estimate of the image plate scale and of the MDI instrumental image distortion. The leakage matrix used for the fitting includes the distortion of the eigenfunctions by the solar differential rotation, and the undistorted leakage matrix was itself carefully reviewed and independently recomputed. Rotation inversions were carried out for all the available mode sets, fitted for that epoch and all available segments, including the MDI and GONG “pipe-line” sets. The improved inversions we used is an iterative methodology based on a least-squares regularization. It also implement a model grid optimization derived from the actual information in the input set. This optimized model grid is itself irregular, namely with a variable number of latitudes at different depths. We not only present the most accurate mean rotation rate, but also how its derivation may still be affected by uncertainties in the mode fitting (in particular the leakage matrix). We also focus on the change of the rotation rate with activity levels and how well these changes are significantly assessed at higher latitudes as well as deeper in the solar interior, down to the base of the convection zone.

66 A determination of high degree mode parameters based on MDI observations S. G. Korzennik1, M. C. Rabello-Soares, J. Schou2 & T. Larson2 1Harvard-Smithsonian Center for Astrophysics, USA 2Stanford University, USA

We present the final determination of high degree mode parameters obtained from the longest full-disk high-resolution data set available from 13 years of MDI operations. A ninety day long time series of full-disk two arc-second per pixel resolution dopplergrams were acquired in 2001, thanks to the high rate telemetry provided by the deep space network. These dopplergrams were decomposed using our best estimate of the image scale and the known components of MDI’s image distortion. The spherical harmonics decomposition was carried out up to l = 1000, and a sine multi-taper power spectrum estimator was used to generate power spectra for all degrees and all azimuthal orders up to l = 1000. We used a large number of tapers, in fact 61, to reduce the realization noise. Since at high degrees the individual modes blend into ridges, there is no reason to preserve a high spectral resolution. These power spectra were fitted for all degrees and all azimuthal orders, between l = 100 and l = 1000, and for all orders with substantial amplitude, generating in excess of 6 million individual estimate of frequencies, line-widths amplitudes and asymmetries, corresponding to some 6,340 singlets. Substantial was here defined as modes having an amplitude at least as large as 1/500 of the largest amplitude at the same degree. Of course the fitting produces only characteristics of the power ridges, characteristics that do not correspond to the underlying mode characteristics. Therefore we used a sophisticated forward modeling of the mode to ridge blending to recover the best possible estimate of the underlying mode characteristics for not only the mode frequency but its line-width, amplitude and asymmetry. We describe this modeling and the iterative process we used to refine its input parameters. Finally not only did we generate corrected mode characteristics and their uncertainties, but an estimate of the precision of the ridge to mode correction itself, in order to assess the magnitude of any residual systematic errors.

67 A paradigm shift in solar dynamo and helioseismic constraints

A. G. Kosovichev1, V. V. Pipin2 & J. Zhao1 1Stanford University, Stanford, CA 94350, USA 2UCLA, Los Angeles, CA 90095, USA

Helioseismology has provided important constraints for the solar dynamo problem. However, the basic properties and even the depth of the dynamo process, which operates also in other stars, are unknown. Most of the dynamo models suggest that the toroidal magnetic field that emerges on the surface and forms sunspots is generated near the bottom of the convection zone, in the tachocline. However, there is a number of theoretical and observational problems with justifying the deep-seated dynamo models. This leads to the idea that the subsurface angular velocity shear may play an important role in the solar dynamo. Using a model of the internal rotation derived from helioseismology, we develop a mean-field MHD model of dynamo distributed in the bulk of the convection zone but shaped in a near-surface layer. We show that if the boundary conditions at the top of the dynamo region allow the large-scale toroidal magnetic fields to penetrate into the surface, then the dynamo wave propagates along the iso-surface of angular velocity in the subsurface shear layer, forming the butterfly diagram in agreement with the Yoshimura rule and solar-cycle observations. We compare this model with inferences of variations of the interior struc- ture, differential rotation, and meridional flows from SOHO/MDI and SDO/HMI helioseismology data.

68 Magnetic flux transportation from decaying sunspot Masahito Kubo National Astronomical Observatory of Japan, Japan

Sunspots are the most prominent magnetic structure on the solar surface. A study on the decay of sunspots as well as the formation is necessary to understand the evolutionary history of sunspots. A transportation of magnetic flux from the sunspots is important to understand the origin of magnetic flux in the quiet Sun and in the polar region. We successfully quantify the magnetic flux budget of the decaying sunspot, for the first time, with the excellent time series of sunspot vector magnetic fields as observed with the Solar Optical Telescope aboard the Hinode satellite. The amount of magnetic flux that decreases in the sunspot is very similar to magnetic flux transported to the outer boundary of the moat region. The flux loss rates of magnetic elements with positive and negative polarities balance each other around the outer boundary of the moat region. The flux budget reveals that most of the magnetic flux disappeared in the sunspot is transported to the outer boundary of the moat region, and then removed from the photosphere by “magnetic flux cancellation” around the outer boundary of the moat region. We also discover that the disintegration of magnetic flux from the sunspot is closely related to convection in the sunspot penumbra. Outward moving bright features at a granular scale in the penumbra appear one and after while magnetic elements are separating from the sunspot. This suggests that subsurface upwelling and diverging flows are formed in the outer penumbra, and such flows work against the stabilization of the sunspot.

69 The first evidence for multiple pulsation axes: a new roAp star in the Kepler field, KIC 10195926 D. W. Kurtz1, M. S. Cunha2, H. Saio3, L. Bigot4, L. A. Balona5, V. G. Elkin1, H. Shiba- hashi6, I. M. Brandao˜ 2, K. Uytterhoeven7, S. Frandsen8, S. Frimann8,9, A. Hatzes10,T. Lueftinger11, M. Gruberbauer12, H. Kjeldsen8, J. Christensen-Dalsgaard8 & S. D. Kawaler13

1University of Central Lancashire, UK 2Universidade do Porto, Portugal 3Tohoku University, Japan 4Universit´eNice Sophia-Antipolis, France 5South African Astronomical Observatory, South Africa 6University of Tokyo, Japan 7CEA, IRFU, France 8Aarhus University, Denmark 9Nordic Optical Telescope, Spain 10Th¨uringerLandessternwarte Tautenburg, Germany 11Universit¨atWien, Austria 12Saint Mary’s University, Canada 13Iowa State University, USA

This talk will introduce the characteristics of the rapidly oscillating Ap stars, then discuss a new rapidly oscillating Ap star discovered by Working Group 5 of the Kepler Asteroseismic Science Con- sortium have discovered a new rapidly oscillating Ap star among the Kepler Mission target stars, KIC 10195926. This star shows two pulsation modes with periods that are amongst the longest known for roAp stars at 17.1 min and 18.1 min, indicating that the star is near the terminal age main sequence. The principal pulsation mode is an oblique dipole mode that shows a rotationally split frequency septuplet that provides information on the geometry of the mode. The secondary mode also appears to be a dipole mode with a rotationally split triplet, but we are able to show within the improved oblique pulsator model that these two modes cannot have the same axis of pulsation. This is the first time for any pulsating star that evidence has been found for separate pulsation axes for different modes. The two modes are separated in frequency by 55 µHz, which we model as the large separation. The star is an α2 CVn spotted magnetic variable that shows a complex rotational light variation with a period of Prot = 5.68459 d. For the first time for any spotted magnetic star of the upper main sequence, we find clear evidence of light variation with a period of twice the rotation period; i.e. a subharmonic frequency of νrot/2. We propose that this and other subharmonics are the first observed manifestation of torsional modes in an roAp star. −1 From high resolution spectra we determine Teff = 7400 K, log g = 3.6 and v sin i = 21 km s . We have found a magnetic pulsation model with fundamental parameters close to these values that reproduces the rotational variations of the two obliquely pulsating modes with different pulsation axes. The star shows overabundances of the rare earth elements, but these are not as extreme as most other roAp stars. The spectrum is variable with rotation, indicating surface abundance patches.

70 Asteroseismology, an essential tool towards accurate stellar ages Y. Lebreton Observatoire de Paris, France

Accurate stellar ages are required for a variety of studies including exoplanet characterization, evolution of galaxies and cosmology. Asteroseismology is an interesting and promising tool for improving the accuracy on stellar ages of large samples of stars all across the H-R diagram. I will discuss the expected progress of asteroseismology compared to other methods by focusing on the bunch of stars for which an asteroseismic age has been determined.

71 Nonlinear coupling coefficient for low frequency modes in rotating stars Umin Lee Astronomical Institute, Tohoku University, Sendai, Miyagi 980-8578, Japan

It is a difficult problem to determine amplitudes of oscillation modes excited in stars. A weak nonlinear theory may give a method to determine the amplitudes, in which nonlinear terms, added to a system of linear oscillation equations, are expected to bring about amplitude saturation as a result of nonlinear coupling between oscillation modes. Oscillation in the nonlinear system may be represented by a series expansion in terms of the eigenfunctions of the linear system, where the expansion coefficients are assumed to be time dependent. Substituting the expansion into the nonlinear equation, we obtain a system of nonlinear equations for the time-dependent expansion coefficients, where the nonlinear terms give coupling coefficients. In this paper, using a weak nonlinear theory for oscillations in rotating stars given by Schenk et al. (2002), I calculate the coupling coefficient for low frequency r-modes and g-modes excited in rotating B-type stars, by taking account of nonlinear coupling with pulsationally stable low frequency modes.

72 Solar atmospheric seismology with HMI and AIA onboard SDO John Leibacher1,2, Kiran Jain1, Rachel Howe1, Fr´ed´eric Baudin2, Bill Chaplin3, Irene Gonzalez´ Hernandez´ 1 Frank Hill1, Shukur Kholikov1, Rudi Komm1 & Sushanta Tripathy1 1National Solar Observatory, Tucson, USA 2Institut d’Astrophysique Spatiale, Orsay, France 3University of Birmingham, UK

We investigate how results from helioseismology are affected by the choice of observable and the height of formation of the spectral line in the solar atmosphere, using high-resolution and high- cadence simultaneous photosphereic Fe i 6173.3 A˚ velocity and intensity observations made by the Helioseismic and Magnetic Imager (HMI) and 1600 and 1700 A˚ continuum measurements made by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to study the effect of systematic errors in helioseismic inferences. Sun-as-a-star, spherical harmonic analysis, ring diagrams, and time–distance analysis are applied to obtain acoustic mode parameters and subsurface flows in localized regions on the solar surface. We compare the results, and interpret these in the context of the differences in the heights of formation of the lines.

73 Meridional flow measurements from GONG John Leibacher & Shukur Kholikov GONG Program, National Solar Observatory, Tucson, Arizona, USA

We present meridional-flow results using time–distance analysis based on GONG data. In an attempt to detect the deep reverse flow, which is believed to be a very small amplitude, we averaged the time–difference measurements over a 15-year period. In order to increase the signal-to-noise ratio, and to reduce contamination from other modes, we utilized both phase velocity and low- m/ℓ filtering techniques. These methods seem to be capable of extending the meridional-flow measurements to the deepest reaches of the convection zone, down to 0.7 R⊙. Our preliminary results indicate that the precision achieved is very close to that required to measure the reverse flow at the base of the solar convection zone: typical error bars for most depths within ±35◦ latitude are less than 0.02 seconds. At higher latitudes, the error bars are about 0.05 seconds.

74 The effect of the initial conditions on stellar rotation, and its impact on oscillation frequencies Joao Pedro Marques Observatoire de Paris, France

It is well known that stellar rotation has an effect in oscillation frequencies. The effect of the initial conditions, however, is less well studied. In this work we examine the effect of the initial conditions on the internal rotation profiles. We consider cases with and without magnetic braking by stellar winds (the former for stars with significant stellar envelopes). We show that the initial conditions can have a substantial effect well into the main sequence phase. We also analyse the effect on other observables, namely the Lithium abundance and rotation period, with applications to gyrochronology.

75 Investigating stellar activity with CoRoT data S. Mathur1, D. Salabert2, C. Regulo´ 3,4, R. A. Garc´ıa5, J. Ballot6 & T. S. Metcalfe1 1High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307, USA 2Universit´ede Nice Sophia-Antipolis, CNRS, Observatoire de la Cˆoted’Azur, BP 4229, 06304 Nice Cedex 4, France 3Universidad de La Laguna, Dpto de Astrof´ısica, 38206, Tenerife, Spain 4Instituto de Astrof´ısica de Canarias, 38205, La Laguna, Tenerife, Spain 5Laboratoire AIM, CEA/DSM – CNRS - Universit´eParis Diderot – IRFU/SAp, 91191 Gif-sur- Yvette Cedex, France 6Laboratoire d’Astrophysique de Toulouse-Tarbes, Universit´ede Toulouse, CNRS, F-31400, Toulouse, France

Recently, the study of the CoRoT target, HD 49933, showed evidence of variability of its magnetic activity. This was the first time that a stellar activity was detected using asteroseismic data. For the Sun and HD 49933, we observe an increase of the p-mode frequencies and a decrease of the maximum amplitude per radial mode when the activity level is higher. Moreover a similar behavior of the frequency shifts with frequency has been found between the Sun and HD 49933. We study 3 other targets of CoRoT as well for which modes have been detected and well identi- fied: HD 181420, HD 49385, and HD 52265 (which is hosting a planet). We show how the seismic parameters (frequency shifts and amplitude) vary during the observation of these stars.

76 Seismic analysis of 4 solar-like stars observed during more than 8 months by Kepler mission S. Mathur1, T. L. Campante2,3, R. Handberg3 et al. 1High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307, USA 2Centro de Astrof´ısica, Faculdade de Ciˆencias,Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 3Danish AsteroSeismology Centre, Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C, Denmark

After more than one year of operation, the Kepler photometer has already provided exquisite data of solar-like stars. For the calibration of the CCD, 42 stars have been continuously observed during the survey phase. It appeared that 5 stars show evidence of oscillations, even though they are rather faint (magnitude from 10.5 to 12). We will show the results of the seismic analysis of the light curves of 4 of these stars, which have been observed during more than 8 months. This analysis led to the determination of the acoustic modes global parameters (mean large separation, mean small separation), lists of frequencies built by comparing the results of several teams, some parameters of the modes, and the rotation period of the stellar surface.

77 Investigating the properties of convection/granulation in the red giants observed by Kepler S. Mathur1, S. Hekker2, R. Trampedach3, et al. 1High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307, USA 2School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3JILA, University of Colorado, 440 UCB, Boulder, CO 80309, USA

More than 1000 red giants have been observed by NASA/Kepler mission during a nearly continuous period of 13 months. The resulting high frequency resolution (¡ 0.03 µHz) allows us to accurately study the granulation parameters of these stars. To do so, we fitted one or several Harvey laws to the power spectra, providing the time scale of granulation and to its amplitude. We show that there is an anti-correlation between these two parameters and the position of maximal power of acoustic modes, while we also find a correlation with the radius and probably with the effective temperature. We finally compare our results with 3D models of the convection.

78 Magnetic field and stellar activitiy across the H-R diagram Gautier Mathys ESO/ALMA, Chile

The research area of stellar magnetism has entered a new era in the last few years with the consid- erable increase of the number of spectropolarimetric instruments in regular operation at various observatories and the spectacular improvement in their performance compared to the previous gen- eration of such instruments. The observations made possible by these instrumental developments have led not only to the discovery of magnetic fields in stars of a large number of types throughout the H-R diagram, but also, and more significantly, combined with ever more detailed and realistic modelling techniques, they have allowed significant insight to be gained into the mechanisms re- sponsible for the generation of the fields and into their interactions with other physical processes taking place in the different types of stars. The picture is complemented by photometric time series obtained within the framework of the CoRoT and Kepler space missions, which allow stellar activity to be characterised in an unprecedented manner. I shall give an overview of our current knowledge of stellar magnetic fields and activity, as it emerges from these recent advances.

79 Pulsational “Rosetta Stones”? MOST seismology of δ Scuti and γ Dor stars Jaymie Matthews University of British Columbia, Canada

The delta Scuti stars have long been a challenge to seismologists. Their observable oscillation spectra have resisted robust fits to unique structural and evolutionary models. Even their period changes and rotational splitting have tended toward the mysterious rather than the model-able. Spacebased photometry of delta Scuti stars has revealed in some cases very rich eigenspectra, and even evidence of granulation in very thin surface convection zones, but reliable asteroseismic fits remain elusive. Recent analyses of MOST photometry may represent breakthroughs: measure- ments of a fundamental spacing pattern in one delta Scuti star (HD 144277), and a rich g-mode spectrum in a rapidly rotating gamma Doradus star (alpha Ophiuchi) whose spin properties are well specified by interferometry. These provide foundations for asteroseismology of these classes of stars.

80 First results from the asteroseismic modeling portal Travis S. Metcalfe High Altitude Observatory, NCAR, USA

Asteroseismology will soon place our understanding of the Sun into a broader context by providing structural information for hundreds of solar-type stars. In the past, ground-based data on solar-like oscillations have emerged slowly enough that we could try to model one star at a time. NASA’s Kepler mission is now producing asteroseismic data for hundreds of stars every few months, so a hands-on approach is a luxury we can no longer afford. We have developed a stellar model- fitting pipeline, which employs a parallel genetic algorithm to match observations from the Kepler mission. We have validated the method using Sun-as-a-star observations as well as data from a wide variety of solar-type stars. The pipeline is now available through the Asteroseismic Modeling Portal (AMP), a Science Gateway website tied to supercomputing resources on the TeraGrid. I will provide an overview of AMP and present some of the first results from its automated analysis of both ground-based and space-based asteroseismic data sets.

81 Oscillation spectra of red giant stars: the predictive power of dipole modes J. Montalban´ 1, A. Miglio1, A. Noels1, R. Scuflaire1 & P. Ventura2 1Universit´ede Li`ege,Belgium 2Osservatorio Astronomico di Roma, Italy

Red giants are cool stars with an extended convective envelope, which can, as in main sequence solar-like stars, stochastically excite pressure modes of oscillation. Although stochastic oscillations were already detected in a few red giants from ground and space observations, one of the most exciting results obtained recently by the space missions COROT and Kepler is the unambiguous detection of radial and non-radial modes in a large number of red-giant stars. The application of theoretical scaling laws, which relate basic seismic observables (the large frequency separation – ∆ν– and the frequency at maximum power –νmax) to the stellar global parameters, led to estimate the masses and radius of CoRoT and KEPLER red giants (adopting a value for the effective temperature). The combination of these scalings with the predictions of population synthesis models led to characterize the population of CoRoT and Kepler targets. These results showing that a vast amount of information can be extracted from quite easy-to-access seismic observables have deeply changed the perception of the predictive capabilities of asteroseismology and have strengthened its interaction with other fields of astrophysics. However, much more information is contained in the oscillation spectra of these large number of red giants. It is theoretically well known that, because of the internal structure properties of red giants (in particular the high value of the central to mean density ratio - density contrast), the non-radial modes in the solar-like oscillation domain are in fact g-p mixed modes, that is modes that propagate in the acoustic (p) and gravity (g) cavities. In this contribution we present a theoretical study of the properties of adiabatic oscillation spectra of red giants stars with different masses and evolution phases (from the red giant branch to the central helium burning phase). We focus on the study of g-p mixed modes and we show that, even if for these objects the asymptotic approximation is no longer valid, it is straightforward to relate the features of the oscillation spectra with the evolutionary state and with properties of the internal structure. That opens the way to the seismic study of the structure and evolution of these objects that play a fundamental role in fields such as stellar age determination and chemical evolution of galaxies.

82 Dynamics in the polar regions of the Sun Kaori Nagashima1, Junwei Zhao1, Alexander G. Kosovichev1 & Takashi Sekii2 1Stanford University, USA 2National Astronomical Observatory of Japan, Japan

We report on study of dynamics of the polar regions of the Sun by a local helioseismology time- distance analysis technique. Exploiting high-resolution datasets obtained by the Solar Optical Telescope on board Hinode, we investigated large-scale flows in the high-latitude regions of the Sun around 80 degrees latitude and above, previously unaccessible for observation. The supergranular cells indicated by the travel-time variations in both the north and the south polar regions show systematic alignment patterns roughly in the north-south direction, and the cells are smaller than their lower-latitude counterparts. Month-long Hinode polar observation campaigns have revealed that this property may be fairly common in the polar regions. Such alignment of supergranular cells in the polar regions has never been predicted by numerical simulations, and is currently unexplained. We will also discuss preliminary results for travel-time signals of differential rotation and meridional flows in the polar region.

83 Numerical simulations of line-profile variation beyond a single- surface approximation Jun Naito, Takashi Nomura & Hiromoto Shibahashi Department of Astronomy, University of Tokyo, Tokyo, Japan

The vertical wavelengths of the oscillations found in roAp stars are so short that the amplitude and phase of variation of each spectroscopic line are highly dependent on the level of the line profile. Hence the analyses of variation of spectroscopic lines of roAp stars potentially provide us with new information about the vertical structure of the atmosphere of these stars. In order to extract such information, we carry out numerical simulation of line profile variation by taking account of finite thickness of the line forming layer. We demonstrate how effective this treatment is, by comparing the simulation with the observed line profiles.

84 Time series UV spectroscopy of GD358 Atsuko Nitta Gemini Observatory, USA

Via HST spectroscopy, we find He II lines in surface spectra of the DBV GD358 and hypothesize they might be due to atmospheric heating during pulsations. GD358 is the most extensively studied pulsating white dwarf star. Its effective temperature has been estimated via optical and UV at about 25,000 K. In 2000, we obtained time series spectroscopic data on GD358 with the HST to compare pulsation amplitudes in the UV and optical. The UV spectra we obtained also revealed, for the first time, lines of H, C and He II, the latter being particularly unusual in a DB cooler than Teff ≅ 80, 000 K. We propose that pulsation heating of the GD358’s atmpshpere is responsible for producing the He II lines.

85 Pulsations of an evolved self-consistently distorted 2 M⊙ Rhita-Maria Ouazzani Observatoire de Paris, France

A new two dimensional non-perturbative method to compute accurate oscillation modes of rapidly rotating stars is presented. The 2D calculations fully take into account the centrifugal distorsion of the star while the non perturbative method include the full in?uence of the Coriolis acceleration. These characteristics give access to the computation of oscillation modes of rapid rotators - high order p-modes in δ Scuti stars, as well as low order p- and g-modes in β Cephei stars. We compare the oscillation spectra obtained for centrifugally distorted polytropes with those of Reese et al. (2006), and give the ?rst results for a realistic 2-dimensional model of a rapidly rotating 2 M⊙ evolved star computed with the method developed by Roxburgh (2006).

86 Challenges in the development of new instrumentation for helio- and asteroseismology ? Pere L. Palle´ Instituto de Astrofisica de Canarias, Spain

The great advances in the knowledge of structure and dynamics of stellar interiors over the past 30 years, in particular of the Sun, is primarily due to novel specific instrumentation and techniques conceived and tested back in the late 70’s and early 80’s. Thanks to the new observational data gathered with this instrumentation, it was possible to improve the current solar models and the development of powerful inversion techniques. In the non-solar domain, Asteroseismology, the situation is quite different as the limitation imposed by earth atmosphere and the lack of unin- terrupted observations has seriously constraint the achievements on this field until the advent of devoted space instrumentation in recent years. It is a matter of thought the fact that, particularly in the Helioseismology domain, current operating instruments on ground and space, are completely based in the concepts and techniques conceived more than 30 years ago. In this respect, despite some attempts, no new instrumental concepts for improving detection of oscillatory signals in the Sun have been yet implemented in working instruments. In broad, it can be stated that the de- velopment of instrumentation in Helioseismology has been at a standstill for the last decades. In the case of Asteroseismology, the great success of present space missions and of the ground high precision spectrometers promises and active development of new instrumental concepts. In this contribution, an overview of the development of instrumentation (past, present and future) in the two fields will be given and some questions to stimulate a broad discussion will be posed.

87 Borderline between asteroseismology and stellar activity § M. Paparo´ Konkoly Observatory, H-1121 Budapest, Konkoly Thege u 15-17, Hungary

The French led CoRoT space mission, beside the seismo field, provided us light curves of thousands of stars with extremely high precision on the exo-fields. The automatic classification seems to be the most plausible solution for the preliminary selection of stars into type of variability. Not only the CoRoT Mission but all the similar upcoming missions are faced with the same difficulty of treating large number of targets (GAIA, PLATO). An example showing confusion between pulsation and stellar activity is presented. It reminds us that in critical cases a final human decision is needed. A different aspect of the increased precision mostly in the space-born datasets is a possible confusion between the intrinsic amplitude variability of pulsation modes excited on low amplitude level and other kind of low amplitude light variability (granulation or activity). Theoretical pulsation models predict many more excited modes on low amplitude level than we observed in the ground-based data. The theoretical frequency spectrum of some type of stars (e.g. Delta Scuti) is so dense that the resolution of the closely spaced modes (if they are real) is a real challenge. An automatic frequency search algorithm cannot control the unrealistic increase in the amplitude of the closely spaced peaks in the multi-frequency analyses. The highly improved number of modes presented in the space-born data analyses warns us that there is a need for human control. We present a case when the intrinsic (not pulsational) variability of an active star can mimic the well-know Blazhko effect of a backgound star.

§The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA’s RSSD and Science Programmes, Austria, Belgium, Brazil, Germany and Spain.

88 Pulsational mode identification based on chromatic ampli- tude behaviour: recent results for rapidly oscillating sub- dwarf B stars S. K. Randall1, G. Fontaine2, P. Brassard2, V. Van Grootel3 & S. Charpinet4 1ESO, Germany 2Universit´ede Montr´eal,Canada 3Universit´ede Li`ege,Belgium 4IRAP, Observatoire Midi-Pyr´en´ees,France

The (partial) identification of observed pulsation modes is a strong asset when attempting the asteroseismological interpretation of any type of pulsator. Indeed, prior information on the de- gree indices of pulsations is often required in order to unambiguously determine the structural parameters of a star through asteroseismology. There are several methods to achieve mode identi- fication, including the analysis of line-profile variations and the moment method, the interpretation of frequency spacings, the incorporation of radial velocity information, and the exploitation of the chromatic amplitude behaviour. We will focus on the latter technique and its application to rapidly pulsating subdwarf B (sdB) stars in this contribution. So far, the exploitation of the chromatic amplitude information in sdB stars has generally been attempted on the basis of time-series multi- colour photometry, and we will present several cases where this has been successful. More recently, we also used time-series spectroscopy to exploit the mono-chromatic amplitude changes for mode identification, with encouraging outcome. We will compare the results obtained from the two approaches and discuss the most efficient strategy to be adopted for mode identification in the future.

89 Phase shift asteroseismological diagnostics for solar like stars Ian Roxburgh Queen Mary University of London, UK

We analyse the properties of p-mode oscillations in solar like stars in terms of acoustic potentials and the phase-shifts of the eigenmodes from simple sine-waves. The phase shifts are the residuals from fitting the frequencies to a lowest order (Vandakurov) asymptotic formula. In the outer layers of a star these phase shifts are effectively independent of degree ℓ, whereas the interior phase shifts are ℓ dependent. Subtraction then eliminates the unknown surface effects on the frequencies and the phase shift difference between modes of degree ℓ and 0 are determined solely by the interior structure. We discuss diagnostic techniques such as the ratio of small to large separations, model fitting, and inversions which are based on these difference. The techniques are applied to some stars observed with CoRoT and Kepler.

90 Long term spectroscopic study of the excited mode stability in the roAp star γ Equ M. Sachkov1, T. Ryabchikova1, W. W. Weiss2, M. Gruberbauer3 & D. Kudryavtsev4 1Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia 2Institute for Astronomy, University of Vienna, Austria 3Department of Astronomy and Physics, St. Mary’s University, Halifax, Canada 4Special Astrophysical Observatory, RAS, Nizhnij Arkhys, Russia

Nineteen time series of high-resolution, high S/N and high time resolution spectra were obtained in the period from 2003 to 2010 with the NES spectrograph of the SAO-RAS 6 m telescope. Aside from rotation, beating with a closely spaced frequency as well as short (∼ 1 day) mode lifetimes have been proposed as the cause of RV and bright amplitude modulation.

RV data have allowed to identify 14 frequencies including the new frequency f3=1.364954 mHz that is very close to the known frequencies f1=1.364594 mHz and f2 = 1.365411 mHz. Based on RV data analysis we conclude that in the roAp star γ Equ excited frequencies are stable on the time scale of several years. All observed highest peak frequencies are close to the frequency pair that was first resolved by Canadian mini-satellite MOST in 2004 data set. Observed amplitude modulation in γ Equ and, possibly, in some other slowly rotating roAp stars can be explained by the existence of such closely spaced frequencies.

91 Physics of stars understood/expected from asteroseismology Hideyuki Saio Astronomical Institute, Graduate School of Science, Tohoku University, Japan

Thanks to the superb photometric data from satellites and spectroscopic data from ground based observations, asteroseismology is now rapidly growing. I will overview briefly on what we have learned for various types of oscillating stars. Then I will discuss what we will potentially be able to learn from stellar oscillations about the interior of stars and the physics of oscillations under the influence of rotation and magnetic fields.

92 A comparison of oscillation frequencies of rotating stars ob- tained by one- and two-dimensional calculations Hideyuki Saio1,2 & Robert G. Deupree2 1Astronomical Institute, Graduate School of Science, Tohoku University, Japan 2Department of Astronomy and Physics, Saint Mary’s University, Canada

Oscillation frequencies and eigenfunctions of a rotating star are shifted due to the effects of Coriolis force and centrifugal deformation of the equilibrium structure. It is important to calculate accurate frequencies of rotating stars to obtain asteroseismological information by comparing theoretical and observed frequencies. The oscillation frequencies can be obtained by two-dimensional calculations for equilibrium structure combined with two-dimensional pulsation analyses, or one-dimensional calculations in which rotation deformation of equilibrium structures are assumed to be proportional to the square of the rotation frequency and eigenfunctions are expanded by using several spherical harmonics. We compare the frequencies obtained by the two methods for 10Msun zero-age main sequence models with various rotation speeds.

93 Helioseismology, solar dynamo, and magnetic helicity Takashi Sakurai National Astronomical Observatory of Japan, Japan

The mechanism of generating and periodically reversing the magnetic fields of the Sun is one of the most fundamental research topics in astrophysics. The dynamo works in the invisible solar interior, so that a combination of helioseismology, numerical simulations, and observations of stellar activity cycles is crucial in order to understand the dynamo process, in addition to the observations of magnetic fields and rotation/flows on the solar surface. Recently, attention has been paid on the latitude distribution of magnetic helicity and its solar-cycle variations, which may give some hints on the behavior of magnetic fields in the solar interior. Difficulties in the current solar dynamo models and prospects for the solution will be discussed.

94 Stellar activity of the seismic solar-like COROT targets I. S. Savanov Institute of Astronomy, RAS, Moscow, Russia

The photospheric spot activity of several stars from the seismic observations by the CoRoT space experiment is reviewed. Their light-curves are fitted by our inversion code that reconstructs the stellar surface spot configuration from the light curve of a rotating star. Our code employs a method that uses the truncated least-squares estimation of the inverse problem’s objects principal components. We use spot filling factors as the unknown object. Our approach allows us to study the longitude distribution of the spotted area and its variations during the period of a typical CoRoT time series. The migration of the spots in longitude provides a lower limit for the surface differential rotation, while flip-flops and variation of the total spotted area can be used to search for short-term cycles. The behaviour of active longitudes and flip-flops on time scales of days-months is also discussed.

95 Multiplicity of rapidly oscillating Ap stars M. Scholler¨ 1, S. Correia2, S. Hubrig2 & D. W. Kurtz3 1European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany 2Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany 3Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, Preston PR1 2HE, United Kingdom

Rapidly oscillating Ap (roAp) stars have rarely been found in binary or higher order multiple systems. We studied the multiplicity of this type of chemically peculiar stars, looking for visual companions in the range of angular separation between 0′′. 05 and 8′′. . A survey of 28 roAp stars was carried out using diffraction limited near infrared imaging with NAOS-CONICA at the VLT. Additionally, we observed three regular A stars. A total of 45 companion candidates were detected. However, out of the eight binary systems found, three are likely change projections. For the five systems, where we found between two and 17 companion candidates, only one companion candidate is very likely not a chance projection. We also found one binary system among the regular A stars. The detected companion candidates have K magnitudes between 6.8 and 19.5 and angular separations ranging from 0′′. 24 to 8′′. 9. While our study confirms that roAp stars are indeed not very often members of binary or multiple systems, we have found four new companion candidates which are likely physical companions.

96 Helioseismic measurements of the torsional oscillation J. Schou1, R. Howe2 & T. P. Larson2 1Stanford University, USA 2National Solar Observatory, USA

The zonal flows known as the torsional oscillation have by now been observed for more than 15 years using observations from MDI and GONG. Even with this limited set of data it is clear that there are significant differences between the cycles, as also evidenced but the prolonged recent solar minimum. Here we discuss some of these differences and their significance. In particular we discuss the slower development of the current solar cycle and the lack of a polar branch in the torsional oscillation. We will also compare results from MDI and HMI and discuss the prospects for generating longer consistent sets of observations.

97 Influence of metallicity and helium abundance on stellar struc- ture and oscillatory properties of stars Hiromoto Shibahashi Department of Astronomy, University of Tokyo, Tokyo, Japan

Theory of helio- and asteroseismology is founded on that of structure and evolution of stars, which is recognized as a well-established subject in astrophysics. Improvement in microphysics relevant to stellar structure and development of various methods and techniques have made helio- and asteroseismology a powerful tool to investigate invisible interiors of the sun and stars and to feed back to progress of our understanding of structure and evolution of stars. In these processes, much efforts have been made to diminish uncertainties in parameters. It should be warned, however, that we are apt to follow up too much only observational, that is, realistic cases. Being apart from the reality might be helpful to understand the physics behind the truth. Along this spirit, in this talk, first, I will demonstrate how helium contents and metallicity affect significantly the stellar structure and evolution. The change in amount of metallicity is of course tiny, but it is sufficient enough to change a familiar sight, as a tiny amount of salt changes sub- stantially a taste of cooking. After then I will show how the stellar properties as oscillators are different from the familiar well-known cases.

98 The Konkoly Blazhko Survey 2 Ad´am´ Sodor´ Konkoly Observatory of the Hungarian Academy of Sciences. P.O. Box 67, H-1525 Budapest, Hungary

The Konkoly Blazhko Survey (KBS) was initiated at the Konkoly Observatory in 2004 using the 60-cm automatic telescope of the institute. The goal of the survey was to collect a large sample of extensive and accurate multicolour light curves of fundamental mode northern galactic field RR Lyrae stars. This large sample permitted not only detailed analysis of the light-curve modula- tion, the so-called Blazhko effect, but the incidence rate of the modulation were also determinable. The first part of the survey (KBS-1) covered 30 variables with periods shorter than 0.5 d. Its results have already been summarized in Jurcsik, S´odor,Szeidl et al. (2009, MNRAS, 400, 1006). Results on individual modulated and non-modulated objects of the sample have also been published in distinct papers¶. The survey was extended in 2009 (KBS-2) toward longer periods, between 0.55 and 0.60 d. The sample of the second part consisted of more than 60 objects. About half of the sample were observed with the 60-cm and 1-m telescopes of the Konkoly Observatory. The rest of the sample were studied using data of public photometric surveys (ASAS, NSVS, Tycho) and data from HAT (Hungarian-made Automated Telescope) observations. Similarly to the results on the KBS-1 sample, we have found that about 50% of the KBS-2 variables show the Blazhko effect. In this presentation, I summarize our preliminary statistical results on the modulated and non-modulated RR Lyrae stars of the KBS-2 sample.

¶See the publication list on our web page for details: http://konkoly.hu/24/publications/

99 Vibrational instability of metal poor stars due to ε-mechanism

Takafumi Sonoi & Hiromoto Shibahashi Department of Astronomy, University of Tokyo, Japan

We carry out the fully nonadiabatic analysis of the vibrational instability due to the ε-mechanism against low degree g modes in population II and III stars. Since the outer convection zone of these stars is very limited only to the very outer layer, the uncertainty in the treatment of convection does not affect the result seriously. We find that stars in the early phase of the hydrogen core burning are unstable. This instability is caused by the ε-mechanism due to the 3He burning in the pp-chain. The decrease in metallicity leads to the decrease in opacity and hence increase in the luminosity of the star. This makes the star compact and this results in the decrease in the density contrast, which is more favorable to the ε-mechanism. We find also that stars in the later phase of the hydrogen core burning are unstable. While the pp-chain dominates the nuclear energy generation in the early phase of the hydrogen core burning, the contribution of the CNO-cycle becomes gradually important with stellar evolution. This causes the growth of the convective core and a superadiabatic zone becomes to appear just outside of the convective core. We find that in such a situation the low degree g modes become unstable due to Kato’s mechanism together with the ε-mechanism. In the case of population III massive stars, the CNO-cycle is activated with the CNO elements produced by the triple alpha reaction which is the main nuclear energy source even at the ZAMS stage. We find that these stars are vibrationally unstable against low degree g modes.

100 Magneto-convection simulation data for local helioseismology analysis Robert F. Stein1, Anders Lagerfjard2, Aake Nordlund2 & Dali Georgobiani1 1Michigan State University, East Lansing, MI, USA 2Niels Bohr Institute, 2100 Kobenhave, Denmark

Data from solar magneto-convection emerging flux simulations is summarized. Uniform, horizontal magnetic field is advected by inflows at the bottom of the domain 48 Mm wide by 20 Mm deep and rises to the surface. The evolution for different field strengths at 20 Mm depth are investigated. The field emerges first in a mixed polarity pepper and salt pattern, but then collects into separate, unipolar concentrations and when enough flux has reached the surface pores are produced. In one case the field strength was artificially increased and then the pores grew into spot-like structures with penumbral-like borders. This data is available for analyzing local helioseismology procedures. Slices of vertical and horizontal velocity, magnetic field strength at continuum optical depths of 0,01, 0.1 and 1 as well as the emergent intensity are available and 4 hour averages (with 2 hour cadence) are being prepared for density, velocity, temperature, energy, sound speed and magnetic field. The data can be found as links from the web page: http://steinr.pa.msu.edu/~bob/. These calculation were performed on the supercomputers of the NASA Advanced Supercomputing Division and were supported by grants from NASA and NSF.

101 Amplitudes of solar-like oscillations in red giant stars: con- straints from open clusters observed by Kepler Dennis Stello1, Sarbani Basu2, Timothy R. Bedding1, Karsten Brogaard3, William J. Chap- lin4, Jørgen Christensen-Dalsgaard3, Yvonne P. Elsworth4, Rafael A. Garc´ıa5, Ronald L. Gilliland6, Frank Grundahl3, Saskia Hekker7, Daniel Huber1, Thomas Kallinger8, Hans Kjeldsen3, Savita Mathur9, Benoˆıt Mosser10 & Graham Verner4 1Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia 2Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 3Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark 4School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 5Laboratoire AIM, CEA/DSM-CNRS, Universit´eParis 7 Diderot, IRFU/SAp, Centre de Saclay, 91191, Gif-sur-Yvette, France 6Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USA 7Astronomical Institute, University of Amsterdam, PO Box 94249, 1090 GE Amsterdam, The Netherlands 8Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 9High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307, USA 10LESIA, CNRS, Universit´ePierre et Marie Curie, Universit´eDenis Diderot, Observatoire de Paris, 92195 Meudon, France

The star clusters observed by the Kepler Mission offers an interesting opportunity for investigating mode amplitudes of solar-like oscillations. In particular, the common distance, age and metallicity of all stars in a cluster provides us with a powerful tool to study how well current scaling relations for mode amplitude match the observations. In this presentation we will show recent results performed on more than 100 red giants in three open clusters, NGC 6791, NGC 6819 and NGC 6811. These clusters span a large range in luminosity (6 L⊙–1500 L⊙) mass (1.2 M⊙–2.35 M⊙), effective temperature (3500 K–5400 K) and metallicity ([Fe/H]∼ 0.0–0.4) which allowed us to explore how the mode amplitude depend on those fundamental stellar parameters.

102 An approach to the exact classification of adiabatic eigen- modes of stars Masao Takata Department of Astronomy, University of Tokyo, Tokyo, Japan

The conventional classification of stellar eigenmodes into p modes, g modes and f modes has not been justified with mathematical completeness yet. Here, we take an approach which is adopted in the field of (geo)seismology. The key point is to transform the governing system of equations into an alternative system in which the dependent variables are the wedge products of the normal variables (perturbed physical quantities). Based on the new system and with an assumption that there is no degeneracy among eigenmodes with the same degree, we can introduce a scheme to define a unique index to each eigenmode which can be used to distinguish among the three kinds of eigenmodes unambiguously.

103 Seismic investigation of chemical stratification in stars Sylvie Theado´ Universit´ede Toulouse, France

The chemical elements present in the stellar material are subject, during the star evolution, to various physical processes which tend to build composition gradients : atomic diffusion, accretion, mass loss, nuclear reactions. In addition to these processes, the stellar matter may experience macroscopic motions which, on the contrary, tend to smooth the chemical stratification : e.g. rotation-induced mixing, convection, thermohaline instabilities, internal gravity waves. The os- cillation properties and (often) their excitation mechanism being highly sensitive to the chemical distribution, their detailed analysis offer a unique opportunity to probe the stellar chemical strat- ification and to infer information about the stellar internal physics. In this talk, I will first review the case where the chemical stratification act as a stabilizing or a driving agent for oscillations. In this context we will see how the constant confrontation between stellar models and seismic obser- vations allows to improve our knowledge of the stellar physics and/or to predict the occurrence of oscillations in “a priori” non-oscillating stars. In a second part I will discuss the effects on strat- ification and pulsations of an often forgotten process in main sequence stars : the thermohaline convection. I will show that this double diffusive instability is a fundamental process which may strongly affect the chemical stratification and must then be included in stellar and derived-seismic computations. At last, in a third part, I will review the possible asteroseismics test of internal chemical composition as well as the first attempts to look for these signatures.

104 3D ring inversions of local helioseismic data: probing flows around sunspots Nicholas F. Featherstone1, Bradley W. Hindman1, Michael J. Thompson2∥ & Juri Toomre1 1University of Colorado, USA 2High Altitude Observatory, USA

We have developed a novel multi-scale 3D inversion procedure for analyzing local helioseismic measurements from ring analysis. The procedure combines data from mosaics of ring tiles of different sizes, enabling fine control of the horizontal resolution and target depth of the inversions. Here we apply our methodology to ring measurements obtained from MDI dopplergrams, in order to investigate the flows around sunspots. We find that the sunspots in our study have surface outflows which diminish with depth in the upper 3 Mm of the convection zone. In many cases, we see what looks like a second outflow at depths of around 5–7 Mm. We discuss the implications for understanding the magneto-hydrodynamic behavior and evolution of sunspots.

∥presenter

105 New era in 3-D modelling of convection and magnetic dy- namos in younger suns and F stars Juri Toomre1, Kyle Augustson1, Benjamin Brown2, Matthew Browning3, Sacha Brun4 & Mark Miesch5 1JILA, Univ Colorado, Boulder, USA 2Astronomy, Univ Wisconsin-Madison, USA 3CITA, Univ Toronto, Canada 4SAp, CEA Saclay, France 5HAO, NCAR, USA

The recent advances in asteroseismology and spectropolarimetry are beginning to provide estimates of differential rotation and magnetic structures realized for a range of F and G-type stars possessing convective envelopes. It is essential to complement such observational work with theoretical studies based on 3-D simulations of highly turbulent convection coupled to rotation, shear and magnetic fields in full spherical geometries. We have so employed the anelastic spherical harmonic (ASH) code, which deals with compressible MHD in spherical shells, to examine the manner in which the global-scale convection can establish differential rotation and meridional circulations under current solar rotation rates, and these make good contact with helioseismic findings. We will here discuss the striking differences realized in G-type stars rotation rather faster than the current sun, thus as is expected when the sun was younger. We find that in such G stars rotating 3 to 5 times faster than the current sun, the convection establishes ever stronger angular velocity contrasts between their fast equators and slow poles, and these are accompanied by prominent latitudinal temperature contrasts as well. Such behavior is retained as magnetic dynamo action is admitted by turning from a hydro to a MHD simulation. The resulting magnetism involves wreaths of strong toroidal magnetic fields (up to 50 to 100 kG strengths) in the bulk of the convection zone, typically of opposite polarity in the north and south hemispheres. These fields can persist for long intervals despite being pummeled by the fast convective downflows, but they can also exhibit field reversals and cycles. Turning to shallower convective envelopes in the more luminous F-type stars that range in mass from 1.2 to 1.4 solar mass and for various rotation rates, we find that the convection can again establish solar-like differential rotation profiles with a fast equator and slow poles, but the opposite is achieved at the slower rotation rates. All possess latitudinal temperature contrasts in rough accord with a thermal wind balance, which again should be taken into account when observing such stars. The F stars are also capable of building strong magnetic fields, often as wreaths, through dynamo action. These simulations of G and F stars are showing that a new era of detailed stellar modelling is becoming feasible through rapid advances in supercomputing, and these have the potential to help interpret and possibly even guide some of the observational efforts now under way.

106 JAXA Solar & helio physics roadmap 2011-2025 Saku Tsuneta National Astronomical Observatory of Japan, Japan

Solar physics from space in Japan started with the launch (1981) of the Hinotori satellite, which carried a modulation collimator for the hard X-ray imaging. This was followed by successful Yohkoh (1991) and Hinode (2006) missions, both of which were built with international collaborations. The latest Hinode carries the high-resolution visible light telescope for the first time, and I will summarize the major discoveries, which are the result of powerful combination of spectroscopy and high resolution. The proposed JAXA-led Solar-C mission should follow these successful missions to resolve two major open issues in solar physics; solar dynamo and chromospheric/coronal heating. Two plans; plan A (out-of-ecliptic helio-seismic mission) and plan B (high resolution spectroscopic mission) have been considered in the ISAS/JAXA Solar-C working group with our international colleagues, and a decision will be made around this April. I will present a Japan’s long strategic plan in solar and helio physics in 2011-2025 and beyond being considered.

107 The long term dynamics of the radiative zone associated to new results from SOHO and young analogs S. Turck-Chieze` 1, S. Couvidat2, V. Duez3, R. A. Garc´ıa1, L. Piau4, D. Salabert5, and the GOLF team

1Service d ’Astrophysique, CEA CE Saclay, France 2HEPL, Stanford University, USA 3Argelander Institut fur Astronomie, Universitat Bonn, Germany 4LATMOS, St Quentin en Yvelines, France 5Observatoire de Nice cˆoted ’azur, Nice, France

Important questions remain unsolved today on the long-term solar internal dynamics. These questions are crucial for a best understanding of the relationship between stars and planets in their first stage or at the present time. By chance, more and more observations about the behaviour and activity of young solar analogs exist and different expressions have been extracted. We use them to determine different scenarios that describe the first stage of evolution of the young Sun. These scenarios include the fact that studies on Mars atmosphere question the initial luminosity of the Sun deduced from SSM hypotheses known as the “solar paradox”. We have in parallel several series of solar data covering three decades, helioseismic modes and neutrino detections are confronted to extract some potential dynamical vestiges of the early phase that contribute to build a dynamical model of the solar interior. Some theoretical results will be presented together with some order of magnitude of specific effects deduced from the different observations. They will help us to describe the secular evolution of the solar rotation, magnetic field, XUV and mass loss, these studies will be also useful for solar like stars. The present studies will be compared to early works on this subject. Part of these works has been published in 2010, new ones will appear in early 2011. See Salabert et al. ApJ lett, 2009, Duez et al. MNRAS, Garc´ıaet al. 2010, SoHO 24; Turck-Chi`ezeet al. ApJ 2010; Turck et al. ApJ lett 2011.

108 Solar Doppler velocity global oscillations of low degrees: the status of GOLF-NG S. Turck-Chieze` 1, J. C. Barriere` 1, P. H. Carton1, V. Duez1, P. Daniel-Thomas1, G. Davies1, R. A. Garc´ıa1, R. Granelli1, C. Lahonde-Hamdoun1, D. Loiseau1, S. Mathis1, F. Nunio1, Y. Piret1, R. Simoniello1, J. Ballot2, S. Mathur3, P. Palle´4 & D. Salabert5 1SAp/CEA/IRFU, France 2Obs. Toulouse, France 3HAO, Boulder, USA 4IAC Spain 5Observatoire de Nice, France

Global oscillations of low degrees are generally considered as the best way to scrutinize the solar core and crucial results have been obtained with the SoHO satellite and the BiSON network. It has been shown recently that they provide also by nature a performing way to follow the varying activity of the sub surface layers. So, they are considered today as a new global indicator of activity, in addition to other well known indicators like radio flux, irradiance, coronal information …, with an undisputed accuracy and a rich information. The simultaneous information coming from radial, dipolar and quadrupolar modes is for example particularly useful to compare the behaviour of the sub surface layers of the two last minima (Salabert et al. 2009). At the end of nineties, the vacation of SoHO, our interest of the gravity modes and the difficulty to detect them has pushed a new instrumental design that improves both characteristics of the detection at low frequencies in comparison with GOLF. We could improve the detectability by a substantial increase of the counting rates to get a higher statistics and a reduction of the solar turbulent noise in measuring simultaneously 7-8 positions in a large spectral line, the sodium line, to benefit from the incoherence of their respective noise. In this poster, we recall the required performances and the technical difficulties to solve. A proto- type has been realized in two phases with laboratory and in situ checks of all the performances at Tenerife. Very encouraging results have been obtained in both phases. All the performances are now solved technically for space observations. We are waiting a substantial improvement of detec- tion of small signals and an improved information as indicators of activity due to the fact that part of the line is sensitive to the magnetic field in the region between photosphere and chromosphere. Continuous observation of these modes after SOHO and SDO leads us to suggest different versions of this instrument, on ground and space to contribute to study the long term variability of the Sun and the potential different origins of this variability.

109 Radiative properties of stellar plasma: the challenges we need to face S. Turck-Chieze` 1, G. Loisel1,2, D. Gilles1, L. Piau1, C. Blancard3, T. Blenski2, M. Bus- quet4, T. Caillaud3, P. Cosse´3, F. Delahaye5, G. Faussurier3, J. Fariaut3, F. Gilleron3, J. A. Guzik6, J. Harris7, D. P. Kilcrease6, N.H. Magee6, J. C. Pain3, Q. Porcherot3, M. Poirier2, G. Soullier3, C. J. Zeippen5, S. Bastiani-Ceccotti8, C. Reverdin3, V. Silvert3, F. Thais2 & B. Villette3 1CEA/DSM/IRFU/SAp, CE Saclay, F-91190 Gif sur Yvette, France 2CEA/DSM/IRAMIS/SPAM, CE Saclay, F-91190 Gif sur Yvette, France 3CEA/DAM/DIF, F-91297 Arpajon, France 4LPGP, Universit´eParis Sud, F-91405 Orsay Cedex, France 5LERMA, Observatoire de Meudon,France 6Theoretical Division, LANL, Los Alamos NM 87545, USA 7AWE, Reading, Berkshire, RG7 4PR, UK 8LULI, Ecole Polytechnique, F-91128 Palaiseau Cedex, France

Radiation plays a crucial role in stars. It determines the longevity of low mass stars, through the transfer of energy and the visible appearance of different types of stars which generally present complex variability. The development of the helio and asteroseismology is rapid, thanks to SoHO, SDO, COROT and KEPLER and in the next decade PLATO. It requires reliable detailed opacity spectra to properly interpret the modes observed. The poster is dedicated to two activities that we are developing; 1) a comparison of codes coming from seven groups involved in astrophysical applications or energy fusion problems for magnetic (ITER) or inertial fusion (LMJ) and 2) different experiments we have already performed in the domain of X and XUV and their theoretical interpretations. We show the interest of the different kinds of calculations: statistical, detailed, mixed. We mention also the difficulties we need to face to get ETL conditions and a proper determination of temperature and density. This effort is supported in France through the consortium OPAC for the confrontation between experiments and calculations of opacity spectra related directly to the development of a new program of inertial fusion for energy.

110 Period and amplitude changes in the GW Vir variable star (PG 1159-type) PG 0122+200: evidence for resonant cou- pling G. Vauclair1, J.-N. Fu2, J.- E. Solheim3, S.- L. Kim4, N. Dolez1, M. Chevreton5, L. Chen2, M.A. Wood6, I. M. Silver6, Zs. Bognar´ 7, M. Paparo´7 & A. H. Corsico´ 8. 1 Institute of Research in Astronomy and Planetology, Universit´ede Toulouse, CNRS, 14 avenue Edouard Belin, 31400 Toulouse, France 2 Department of Astronomy, Beijing Normal University, 100875 Beijing, China 3 Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029, Blindern, N-0315 Oslo, Norway 4 Korea Astronomy and Space Science Institute, San 61-1, Hwaam, Yuseong, 305-348 Daejeon, Korea 5 LESIA, Observatoire de Paris-Meudon, Meudon, France 6 Department of Physics and Space Sciences & SARA Observatory, Florida Institute of Technology, Florida 32901, USA 7 Konkoly Observatory, PO Box 67, 1525 Budapest, Hungary 8 Facultad de Ciencias Astron´omicas y Geof´ısicas, Universidad Nacional de La Plata, Observatorio- Paseo del Bosque S/N, B1900FWA La Plata, Argentina

The PG 1159 pre-white dwarf stars experiment a rapidly cooling phase with time scale of a few 106 years. Theoretical models predict that the neutrinos should play a dominant role in the cooling, mainly at the cool end of the PG 1159 sequence. Measuring the evolutionary time scale of the coolest PG 1159 stars was expected to offer a unique opportunity to constrain the neutrino emission rate. A subgroup of the PG 1159 stars are nonradial pulsators, the GW Vir type of variable stars. They exhibit g-mode pulsations with periods of a few hundreds seconds. As the stars cool, the frequencies evolve according to the change in their internal structure. It was anticipated that the measurement of their rate of change would provide a direct determination of the evolution time scale, and so constrain the neutrino emission rates. As PG 0122+200 (BB Psc) defines the red edge of the GW Vir instability strip, it was a good candidate for such a measurement. The pulsations of PG 0122+200 have been observed during 22 years, from 1986 to 2008. We used those data to measure the rate of change of its frequencies and amplitudes. Among the 24 identified ℓ=1 modes, the frequency and amplitude variations have been obtained for the seven largest amplitude ones. We find changes of their frequency of much larger amplitudes and shorter time scales than the one predicted by theoretical models which assume that the cooling dominates the frequency variations. In the case of the largest amplitude mode at 2497 µHz (400 s), its variations are best fitted by a combination of two terms: one long term with a time scale of 5.4 × 104 years, which is significantly shorter than the predicted evolutionary time scale of 8×106 years, and one additional periodic term with a period of either 261 or 211 days. We suggest that the resonant coupling induced within triplets by the star rotation could be the mechanism producing such frequency and amplitude variations.

111 Asteroseismology of exoplanets-host-stars: the helium prob- lem and other associate effects Sylvie Vauclair Universite de Toulouse, and Institut Universitaire de France, France

More than 500 planets are presently known to orbit around stars other than the Sun. The charac- terization of these planetary systems need a precise determination of the parameters of the central stars (masses, radii, ages, abundances, etc.). In this framework, asteroseismology represents an important tool which may lead to precisions never reached before. At the present time, with large data basis, it becomes necessary to find automatic solutions to these parameters determinations. However systematic uncertainties do remain and the final models are not unique, due to several problems including the internal helium abundance. Detailed studies of individual stars help finding solutions to such difficulties. I will discuss such studies for some well observed Exoplanets-Hosts Stars obtained from ground based or space observations and give conclusions for future prospects.

112 The enigmatic pulsation of γ Equ M. Gruberbauer1, M. Sachkov2, W. W. Weiss3, T. Ryabchikova2, J. Matthews4, R. Kuschnig3 & D. Kudryavtsev5 1Dept. of Astronomy and Physics, St. Mary’s University, Halifax, Canada 2Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia 3Institute for Astronomy, University of Vienna, Austria 4University of British Columbia, Vancouver, Canada 5Special Astrophysical Observatory, RAS, Nizhnij Arkhys, Russia

After two observing runs of the Canadian space telescope MOST we are in the unique position to investigate the nature of one of the most well-studied, but still enigmatic roAp stars: γ Equ. The 2004 photometric data set shows much more detail than known bef ore from ground-based photometry or spectroscopy. To our surprise we learned from the recent 2010 MOST data that our picture of γ Equ indicated by the 2004 data still is too simple. Some modes have disappeared, some seem shifted in frequency, some remain e xactly the same. It is thanks to MOST that we can be sure that this is an intrinsic change in γ Equ, and not caused by limited data quality. Parallel to the MOST photometry a comparably voluminous spectroscopic observing program was pursued. Nineteen time series of spectra were obtained in the period from 2003 to 2010 with the NES spectrograph of the SAO-RAS 6 m telescope. Note that the high a mplitudes of RV variations potentially allow to obtain mode frequencies even for rather short spectroscopic data strings, but with the penalty of an aliasing problem for such data sets with a poor duty cycle. A high duty cycle is the strength of the cont inuous MOST data but which, on the other hand, suffer of very small photometric amplitudes for more complex modes. Hence, the synergy of continuous MOST photometry during several weeks and contemporane- ous time-series spectroscopy of γ Equ even during few nights is crucial for our understanding of pulsation at the surface and underneath. MOST provides the set of intrins ic pulsation frequen- cies thanks to its clean window function, and spectroscopy the dynamic characteristics of various atmospheric layers via studying individual elements and spectral lines. The frequency variability inferred from the 2010 data sets needs to be traced with new observations in order to 1.) find a model to confirm and explain the frequency changes in terms of secular changes from the 2004 MOST run as well as throughout the large archive of spectroscopic and photometric ground-based data. 2.) trace future variations. 3.) build a large data set that can be combined to study a possibly stochastic nature of the signal.

113 Interaction of helioseismic waves with sunspots: observations and numerical MHD simulations Junwei Zhao, Konstantin V. Parchevsky & Alexander G. Kosovichev Stanford University, USA

We investigate how helioseismic waves that originate from effective point sources interact with sunspots. For observations, the waves from point sources are reconstructed by cross-correlating observed photospheric Doppler signals. For numerical simulations, the waves are generated by simulating perturbation propagation from a pulse near the surface and propagate through mag- netostatic and MHD sunspot models. For both cases, we study f-mode wave and p-mode waves separately. We also study different cases when the point source is located outside the sunspot, and when the source is located inside the sunspot. Our results nicely visualize how the waves, including both wave amplitudes and phases, interact with the magnetic field, thermodynamic and flow structure of sunspots, and how the wave forms evolve before, during, and after the propa- gation through sunspots. Our analysis of wave-magnetic field interactions also extends below the sunspot’s surface. This brings us new rich information of how the waves respond to the magnetic field below the surface, but also poses new challenges for local helioseismology to infer the sunspot’s interior properties from the wave-form observations.

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Participants List

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116 Country Name Affilliation Argentina C´orsico,A. H. Universidad Nacional de La Plata Australia Bedding, T. R. University of Sydney Stello, D. University of Sydney Austria Houdek, G. University of Vienna Weiss, W. W. University of Vienna Belgium Aerts, C. Katholieke Universiteit Leuven Belkacem, K. Universit´ede Li`ege Godart, M. Universit´ede Li`ege Grevesse, N. Universit´ede Li`ege Montalb´an,J. Universit´ede Li`ege Brazil Kanaan, A. Universidade Federal de Santa Catarina Kepler, S. O. Universidade Federal do Rio Grande do Sul Canada Fontaine, G. Universit´ede Montr´eal Kallinger, T. University of British Columbia Matthews, J. University of British Columbia Chile Mathys, G. ESO/ALMA Denmark Christensen-Dalsgaard, J. Aarhus University France Alecian, G. Observatoire de Paris Appourchaux, T. Universit´eParis Sud Baglin, A. Observatoire de Paris Ballot, J. Universit´ede Toulouse Baudin, F. Institut d’Astrophysique Spatiale, Orsay Brun, A. S. Service d’Astrophysique, CEA CE Saclay Charpinet, S. Universit´ede Toulouse Garc´ıa,R. A. Service d’Astrophysique, CEA CE Saclay Goupil, M.-J. Observatoire de Paris Lebreton, Y. Observatoire de Paris Marques, J. P. Observatoire de Paris Michel, E. Observatoire de Paris Ouazzani, R.-M. Observatoire de Paris Th´eado,S. Universit´ede Toulouse Turck-Chi`eze,S. Service d’Astrophysique, CEA CE Saclay Vauclair, G. Universit´ede Toulouse Vauclair, S. Universit´ede Toulouse, & Institut Universitaire de France Germany Gizon, L. Max Planck Institute for Solar System Research Hubrig, S. Astrophysical Institute Potsdam Randall, S. K. ESO Sch¨oller,M. ESO Hungary Papar´o,M. Konkoly Observatory S´odor, A.´ Konkoly Observatory Italy Di Mauro, M. P. Istituto di Astrofisica Spaziale e Fisica Cosmica Japan Ando, H. National Astronomical Observatory Ishimatsu, H. University of Tokyo Kambe, E. National Astronomical Observatory Kubo, M. National Astronomical Observatory Lee, U. Tohoku University Naito, J. University of Tokyo Osaki, Y. University of Tokyo Saio, H. Tohoku University Sakurai, T. National Astronomical Observatory table continued on next page

117 continued from previous page Country Name Affilliation Sekii, T. National Astronomical Observatory Shibahashi, H. University of Tokyo Sonoi, T. University of Tokyo Takata, M. University of Tokyo Tsuneta, S. National Astronomical Observatory Netherlands Hekker, S. University of Amsterdam Poland Baran, A. Cracow Pedagogical University, & Iowa State University Handler, G. Nicolaus Copernicus Astronomical Center Russia Sachkov, M. E. Institute of Astronomy, Russian Academy of Sciences Savanov, I. S. Institute of Astronomy, Russian Academy of Sciences South Africa Balona, L. A. South African Astronomical Observatory Spain Pall´e,P. L. Instituto de Astrof´ısicade Canarias R´egulo,C. Instituto de Astrof´ısicade Canarias Taiwan Chou, D.-Y. National Tsing Hua University U.K. Chaplin, W. J. University of Birmingham Gough, D. O. University of Cambridge Hu, H. University of Cambridge Jeffery, C. S. Armagh Observatory Kurtz, D. W. University of Central Lankashire Lynas-Gray, A. E. University of Oxford Roxburgh, I. W. Queen Mary University of London U.S.A. Basu, S. Yale University Bischoff-Kim, A. Georgia College & State University Couvidat, S. Stanford University Duvall, T. L., Jr. NASA, GSFC Hamerly, R. Stanford University Hill, F. National Solar Observatory Ilonidis, S. Stanford University Kitiashvili, I. N. Stanford University Kleinman, S. J. Gemini Observatory Korzennik, S. G. Harvard University Kosovichev, A. G. Stanford University Leibacher, J. National Solar Observatory Mathur, S. High Altitude Observatory Metcalfe, T. S. High Altitude Observatory Nagashima, K. Stanford University Nitta, A. Gemini Observatory Schou, J. Stanford University Stein, R. F. Michigan State University Thompson, M. J. High Altitude Observatory Toomre, J. University of Colorado Zhao, J. Stanford University

118 Email addresses

Name email Aerts, C. [email protected] Alecian, G. [email protected] Ando, H. [email protected] Appourchaux, T. [email protected] Baglin, A. [email protected] Ballot, J. [email protected] Balona, L. A. [email protected] Baran, A. [email protected] Basu, S. [email protected] Baudin, F. [email protected] Bedding, T. R. [email protected] Belkacem, K. [email protected] Bischoff-Kim, A. [email protected] Brun, A.S. [email protected] Chaplin, W. J. [email protected] Charpinet, S. [email protected] Chou, D.-Y. [email protected] Christensen-Dalsgaard, J. [email protected] C´orsico,A. H. [email protected] Couvidat, S. [email protected] Di Mauro, M.P. [email protected] Duvall, T. L., Jr. [email protected] Fontaine, G. [email protected] Garc´ıa,R. A. [email protected] Gizon, L. [email protected] Godart, M. [email protected] Gough, D. O. [email protected] Goupil, M.-J. [email protected] Grevesse, N. [email protected] Hamerly, R. [email protected] Handler, G. [email protected] Hekker, S. [email protected] Hill, F. [email protected] Houdek, G. [email protected] Hu, H. [email protected] Hubrig, S. [email protected] Ilonidis, S. [email protected] Ishimatsu, H. Jeffery, C. S. [email protected] Kallinger, T. [email protected] Kambe, E. [email protected] Kanaan, A. [email protected] Kepler, S. O. [email protected] Kitiashvili, I. [email protected] Kleinman, S. J. [email protected] Korzennik, S. G. [email protected] Kosovichev, A. G. [email protected] Kubo, M. [email protected] Kurtz, D. W. [email protected] table continued on next page 119 continued from previous page Name email Lebreton, Y. [email protected] Lee, U. [email protected] Leibacher, J. [email protected] Lynas-Gray, A. E. [email protected] Marques, J. P. [email protected] Mathur, S. [email protected] Mathys, G. [email protected] Matthews, J. [email protected] Metcalfe, T. S. [email protected] Michel, E. [email protected] Montalb´an,J. [email protected] Nagashima, K. [email protected] Naito, J. [email protected] Nitta, A. [email protected] Osaki, Y. [email protected] Ouazzani, R. M. [email protected] Pall´e,P. L. [email protected] Papar´o,M. [email protected] Randall, S. K. [email protected] R´egulo,C. [email protected] Roxburgh, I. W. [email protected] Sachkov, M. E. [email protected] Saio, H. [email protected] Sakurai, T. [email protected] Savanov, I. S. [email protected] Sch¨oller,M. [email protected] Schou, J. [email protected] Sekii, T. [email protected] Shibahashi, H. [email protected] S´odor, A.´ [email protected] Sonoi, T. [email protected] Stein, R. F. [email protected] Stello, D. [email protected] Takata, M. [email protected] Th´eado,S. [email protected] Thompson, M. J. [email protected] Toomre, J. [email protected] Tsuneta, S. [email protected] Turck-Chi`eze,S. [email protected] Vauclair, G. [email protected] Vauclair, S. [email protected] Weiss, W. W. [email protected] Zhao, J. [email protected]

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