JAAVSO 2009 the Journal of the American Association of Variable Star Observers
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Unknown Amorphous Carbon II. LRS SPECTRA the Sample Consists Of
Table I A summary of the spectral -features observed in the LRS spectra of the three groups o-f carbon stars. The de-finition o-f the groups is given in the text. wavelength Xmax identification Group I B - 12 urn E1 9.7 M™ Silicate 12 - 23 jim E IB ^m Silicate Group II < 8.5 M"i A C2H2 CS? 12 - 16 f-i/n A 13.7 - 14 Mm C2H2 HCN? 8 - 10 Mm E 8.6 M"i Unknown 10 - 13 Mm E 11.3 - 11 .7 M«> SiC Group III 10 - 13 MJn E 11.3 - 11 .7 tun SiC B - 23 Htn C Amorphous carbon 1 The letter in this column indicates the nature o-f the -feature: A = absorption; E = emission; C indicates the presence of continuum opacity. II. LRS SPECTRA The sample consists of 304 carbon stars with entries in the LRS catalog (Papers I-III). The LRS spectra have been divided into three groups. Group I consists of nine stars with 9.7 and 18 tun silicate features in their LRS spectra pointing to oxygen-rich dust in the circumstellar shell. These sources are discussed in Paper I. The remaining stars all have spectra with carbon-rich dust features. Using NIR photometry we have shown that in the group II spectra the stellar photosphere is the dominant continuum. The NIR color temperature is of the order of 25OO K. Paper II contains a discussion of sources with this class of spectra. The continuum in the group III spectra is probably due to amorphous carbon dust. -
Introduction
Introduction ”They say the sky is the limit, but to me, it is only the beginning. I look to the stars, and I count them, imagining every one of them as the centre of a solar system, even more wondrous than our own. We now know they are out there. Planets. Millions of them - just waiting to be discovered. What are they like, these distant spinning worlds? How did they come to be? And finally - before I close my eyes and go to sleep, one question lingers. Like the echo of a whisper : Is anyone out there...” The study of exoplanets is a quest to understand our place in the universe. How unique is the solar system? How extraordinary is the Earth? Is life on Earth an unfathomable coincidence, or is the galaxy teeming with life? Only 25 years ago the first extrasolar planets were discovered, two of them, orbiting the millisecond pulsar PSR1257+12 (Wolszczan and Frail, 1992), and this was followed three years later by the discovery of the first exoplanet orbiting a solar-type star (51 Pegasi, Mayor and Queloz, 1995). In the subsequent years, multiple techniques were developed to find and study these new worlds. Each detection method has its own advantages, limitations and biases, and they have complimented each other to form the picture of exoplanets that we have today: The galaxy is brimming with planetary systems, and the exoplanets are more diverse, than we could ever have imagined. The diversity of planets presents a challenge to the theories of formation designed to match the solar system, and any modern theories must strive to explain the full observed range of architectures of planetary systems. -
Employee Wellbeing at Cornell Re
Your guide to resources that support all the dimensions of your wellbeing. HR.CORNELL.EDU/WELLBEING 1 2 1.6.20 Dear Colleague, During your time with Cornell, we want you to be well and THRIVE. Cornell invests in benefits, programs, and services to support employee wellbeing. This guide features a wide range of university (and many community!) resources available to support you in various dimensions of your wellbeing. As you browse this guide, which is organized around Cornell’s Seven Dimensions of Wellbeing model pictured below, you’ll find many resources cross-referenced in multiple dimensions. This illustrates the multifaceted nature of wellbeing. It is often non-linear in nature, and our most important elements shift as our work and Mary Opperman personal lives evolve. CHRO and Vice President Division of Human Resources We experience wellbeing both personally and as members of our various communities, including our work community. We each have opportunities to positively contribute to Cornell’s culture of wellbeing as we celebrate our colleagues’ life events, support one another during difficult times, share resources, and find creative approaches to how, where, and when work gets done. Behind this page is a “quick start directory” of Cornell wellbeing-related contacts. Please save this page and reach out any time you need assistance! Although some of these resources are specific to Cornell’s Ithaca campus, we recognize and are continuing to focus on expanding offerings to our employees in all locations. Thank you for all of your contributions -
Messenger-No117.Pdf
ESO WELCOMES FINLANDINLAND AS ELEVENTH MEMBER STAATE CATHERINE CESARSKY, ESO DIRECTOR GENERAL n early July, Finland joined ESO as Education and Science, and exchanged which started in June 2002, and were con- the eleventh member state, following preliminary information. I was then invit- ducted satisfactorily through 2003, mak- II the completion of the formal acces- ed to Helsinki and, with Massimo ing possible a visit to Garching on 9 sion procedure. Before this event, howev- Tarenghi, we presented ESO and its scien- February 2004 by the Finnish Minister of er, Finland and ESO had been in contact tific and technological programmes and Education and Science, Ms. Tuula for a long time. Under an agreement with had a meeting with Finnish authorities, Haatainen, to sign the membership agree- Sweden, Finnish astronomers had for setting up the process towards formal ment together with myself. quite a while enjoyed access to the SEST membership. In March 2000, an interna- Before that, in early November 2003, at La Silla. Finland had also been a very tional evaluation panel, established by the ESO participated in the Helsinki Space active participant in ESO’s educational Academy of Finland, recommended Exhibition at the Kaapelitehdas Cultural activities since they began in 1993. It Finland to join ESO “anticipating further Centre with approx. 24,000 visitors. became clear, that science and technology, increase in the world-standing of ESO warmly welcomes the new mem- as well as education, were priority areas Astronomy in Finland”. In February 2002, ber country and its scientific community for the Finnish government. we were invited to hold an information that is renowned for its expertise in many Meanwhile, the optical astronomers in seminar on ESO in Helsinki as a prelude frontline areas. -
The Planets for 1955 24 Eclipses, 1955 ------29 the Sky and Astronomical Phenomena Month by Month - - 30 Phenomena of Jupiter’S S a Te Llite S
THE OBSERVER’S HANDBOOK FOR 1955 PUBLISHED BY The Royal Astronomical Society of Canada C. A. C H A N T, E d ito r RUTH J. NORTHCOTT, A s s is t a n t E d ito r DAVID DUNLAP OBSERVATORY FORTY-SEVENTH YEAR OF PUBLICATION P r i c e 50 C e n t s TORONTO 13 Ross S t r e e t Printed for th e Society By the University of Toronto Press THE ROYAL ASTRONOMICAL SOCIETY OF CANADA The Society was incorporated in 1890 as The Astronomical and Physical Society of Toronto, assuming its present name in 1903. For many years the Toronto organization existed alone, but now the Society is national in extent, having active Centres in Montreal and Quebec, P.Q.; Ottawa, Toronto, Hamilton, London, and Windsor, Ontario; Winnipeg, Man.; Saskatoon, Sask.; Edmonton, Alta.; Vancouver and Victoria, B.C. As well as nearly 1000 members of these Canadian Centres, there are nearly 400 members not attached to any Centre, mostly resident in other nations, while some 200 additional institutions or persons are on the regular mailing list of our publications. The Society publishes a bi-monthly J o u r n a l and a yearly O b s e r v e r ’s H a n d b o o k . Single copies of the J o u r n a l are 50 cents, and of the H a n d b o o k , 50 cents. Membership is open to anyone interested in astronomy. Annual dues, $3.00; life membership, $40.00. -
Pos(HTRA-IV)023 , 1 , 9 , B.T
ULTRACAM observations of SDS 0926+3624: the first known eclipsing AM CVn star PoS(HTRA-IV)023 C.M. Copperwheat∗ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK E-mail: [email protected] T.R. Marsh1, S.P. Littlefair2, V.S. Dhillon2, G. Ramsay3, A.J. Drake4, B.T. Gänsicke1, P.J. Groot5, P. Hakala6, D. Koester7, G. Nelemans5, G. Roelofs8, J. Southworth9, D. Steeghs1 and S. Tulloch2 1 Department of Physics, University of Warwick, Coventry, CV4 7AL, UK 2 Department of Physics and Astronomy, University of Sheffield, S3 7RH, UK 3 Armagh Observatory, College Hill, Armagh, BT61 9DG, UK 4 California Institute of Technology, 1200 E. California Blvd., CA 91225, USA 5 Department of Astrophysics, IMAPP, Radboud University Nijmegen, PO Box 9010, NL-6500 GL Nijmegen, the Netherlands 6 Finnish Centre for Astronomy with ESO, Tuorla Observatory, Väisäläntie 20, FIN-21500 Piikkiö, University of Turku, Finland 7 Institut für Theoretische Physik und Astrophysik, Universität Kiel, 24098 Kiel, Germany 8 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 9 Astrophysics Group, Keele University, Newcastle-under-Lyme, ST5 5BG, UK The AM Canum Venaticorum (AM CVn) stars are ultracompact binaries with the lowest periods of any binary subclass, and consist of a white dwarf accreting material from a donor star that is it- self fully or partially degenerate. These objects offer new insight into the formation and evolution of binary systems, and are predicted to be among the strongest gravitational wave sources in the sky. To date, the only known eclipsing source of this type is the 28 min binary SDSS 0926+3624. -
Rapid Oscillations in Cataclysmic Variables
I RAPID OSCILLATIONS IN CATACLYSMIC VARIABLES Sue Allen . ' Thesis submitted for the degree of l Master of Science at the University of Cape Town July 1986 'I.-~~,,,.,------.. The Unlvers{ty bf qape Town tias been given the right to reproduce t~!s thesis in whole or in part. Copytlght Is hehl ~y the author. The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgement of the source. The thesis is to be used for private study or non- commercial research purposes only. Published by the University of Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. ACKNOWLEDGEMENTS I am indebted to my supervisor, Professor B. Warner, for his guidance and patience and for securing me financial support for this work. I am·· grateful to the Director of the south African Astronomical Observatory, Dr M. Feast, for the allocation of observing time and for' allowing me to use the Observatory Library over an extended period .. Thanks also to Mrs E:. Lastovica and Dr L. Balona, and especially to Drs o. Kilkenny and I. Coulson for constant encouragement and for putting up with a "squatter" in their office. Dr o. O'Donoghue wrote all the computer programs used in the data analysis, and gave me great moral support and much of his time. My thanks go to Mrs P. Debbie and Mrs c. Barends for help with the worst of the typing, and to Dr I. Coulson for proofreading the manuscript. -
A Review of the Disc Instability Model for Dwarf Novae, Soft X-Ray Transients and Related Objects a J.M
A review of the disc instability model for dwarf novae, soft X-ray transients and related objects a J.M. Hameury aObservatoire Astronomique de Strasbourg ARTICLEINFO ABSTRACT Keywords: I review the basics of the disc instability model (DIM) for dwarf novae and soft-X-ray transients Cataclysmic variable and its most recent developments, as well as the current limitations of the model, focusing on the Accretion discs dwarf nova case. Although the DIM uses the Shakura-Sunyaev prescription for angular momentum X-ray binaries transport, which we know now to be at best inaccurate, it is surprisingly efficient in reproducing the outbursts of dwarf novae and soft X-ray transients, provided that some ingredients, such as irradiation of the accretion disc and of the donor star, mass transfer variations, truncation of the inner disc, etc., are added to the basic model. As recently realized, taking into account the existence of winds and outflows and of the torque they exert on the accretion disc may significantly impact the model. I also discuss the origin of the superoutbursts that are probably due to a combination of variations of the mass transfer rate and of a tidal instability. I finally mention a number of unsolved problems and caveats, among which the most embarrassing one is the modelling of the low state. Despite significant progresses in the past few years both on our understanding of angular momentum transport, the DIM is still needed for understanding transient systems. 1. Introduction tems using Doppler tomography techniques (Steeghs et al. 1997; Marsh and Horne 1988; see also Marsh and Schwope Dwarf novae (DNe) are cataclysmic variables (CV) that 2016 for a recent review). -
Present Status and Future Directions of the EVN
http://www.evlbi.org/ Present status and future directions of the EVN Michael Lindqvist, Onsala Space Observatory Zsolt Paragi, JIVE Onsala Space Observatory http://www.evlbi.org/ Thanks Tasso! Onsala Space Observatory http://www.evlbi.org/ VLBI science • Radio jet & black hole physics • Radio source evolution • Astrometry • Galactic and extra-galactic masers • Gravitational lenses • Supernovae and gamma-ray-burst studies • Nearby and distant starburst galaxies • Nature of faint radio source population • HI absorption studies in AGN • Space science VLBI • Transients • SETI Onsala Space Observatory http://www.evlbi.org/ Description of the EVN • The European VLBI Network (EVN) was formed in 1980. Today it includes 15 major institutes, including the Joint Institute for VLBI ERIC, JIVE • JIVE operates EVN correlator. JIVE is also involved in supporting EVN users and operations of EVN as a facility. JIVE has officially been established as an European Research Infrastructure Consortium (ERIC). • The EVN operates an “open sky” policy • No standing centralised budget for the EVN - distributed European facility Onsala Space Observatory http://www.evlbi.org/ The network Onsala Space Observatory http://www.evlbi.org/ EVN and e-VLBI From tape reel to intercontinental light paths • Pieces falling into place around 2003: – Introduction of Mark5 recording system (game changer) by Haystack Observatory – Emergence of high bandwidth optical fibre networks e-VLBI JIVE Hot scienceJIVE • The development of e-VLBI has been spearheaded by the JIVE/EVN (EXPReS, Garrett) • In this way, the EVN/JIVE is a recognized SKA pathfinder Onsala Space Observatory http://www.evlbi.org/ e-VLBI - rapid turn-around • e-VLBI has made rapid turn-around possible – X-ray, γ-ray binaries in flaring states (including novae) – AGN γ-ray outbursts — locus of VHE emission – Other high-energy flaring (e.g., Crab) – Outbursts in Mira variables (spectral-line) – Just-exploded GRBs, SNe – Binaries (incl. -
ESO Staff Papers 08/2012 Papers Added Recently to the ESO Telescope Bibliography, Maintained by the Library Subscribe to the ESO Telbib RSS Feed
ESO staff papers 08/2012 Papers added recently to the ESO Telescope Bibliography, maintained by the library Subscribe to the ESO telbib RSS feed Cosmology | Galaxies and Galactic Nuclei | Interstellar Medium, Star Formation and Planetary Systems | Stellar Evolution | Miscellaneous | Papers without ESO data Cosmology | Galaxies and Galactic Nuclei | Interstellar Medium, Star Formation and Planetary Systems | Stellar Evolution | Miscellaneous: ESO authors + ESO observational data Cosmology Metallicities, Dust, and Molecular Content of a QSO-damped Lyα System Reaching log N(H I) = 22: An Analog to GRB-DLAs Guimarães, R., Noterdaeme, P., Petitjean, P., Ledoux, C., Srianand, R., López, S., & Rahmani, H., 2012, AJ, 143, 147 [ADS] Instruments: UVES, UVES The Optically Unbiased GRB Host (TOUGH) Survey. IV. Lyα Emitters Milvang-Jensen, B., Fynbo, J.P.U., Malesani, D., Hjorth, J., Jakobsson, P., & Møller, P., 2012, ApJ, 756, 25 [ADS] Instruments: FORS1, FORS1, FORS1, FORS1, FORS1 Herschel-PACS far-infrared detections of Lyman-α emitters at 2.0 z 3.5 Oteo, I., Bongiovanni, A., Pérez García, A.M., Cepa, J., Ederoclite, A., Sánchez-Portal, M., Pintos-Castro, I., Pérez- Martínez, R., Berta, S., Magnelli, B., Popesso, P., Pozzi, F., Poglitsch, A., Lutz,≲ ≲ D., Genzel, R., Tacconi, L., Förster Schreiber, N., Sturm, E., Elbaz, D., Aussel, H., Daddi, E., Andreani, P., Cimatti, A., Maiolino, R., Altieri, B., & Valtchanov, I., 2012, A&A, 541, 65 [ADS] Instruments: FORS2, ISAAC, ISAAC, ISAAC, ISAAC, WFI, WFI, WFI, WFI, VIMOS, VIMOS Physical Properties of Lyα -
The Atmospheric Parameters of FGK Stars Using Wavelet Analysis of CORALIE Spectra S
A&A 612, A111 (2018) https://doi.org/10.1051/0004-6361/201731954 Astronomy & © ESO 2018 Astrophysics The atmospheric parameters of FGK stars using wavelet analysis of CORALIE spectra S. Gill, P. F. L. Maxted, and B. Smalley Astrophysics Group, Keele University, Keele ST5 5BG, UK e-mail: [email protected] Received 14 September 2017 / Accepted 18 January 2018 ABSTRACT Context. Atmospheric properties of F-, G- and K-type stars can be measured by spectral model fitting or with the analysis of equivalent width (EW) measurements. These methods require data with good signal-to-noise ratios (S/Ns) and reliable continuum normalisation. This is particularly challenging for the spectra we have obtained with the CORALIE échelle spectrograph for FGK stars with transiting M-dwarf companions. The spectra tend to have low S/Ns, which makes it difficult to analyse them using existing methods. Aims. Our aim is to create a reliable automated spectral analysis routine to determine Teff , [Fe/H], V sin i from the CORALIE spectra of FGK stars. Methods. We use wavelet decomposition to distinguish between noise, continuum trends, and stellar spectral features in the CORALIE spectra. A subset of wavelet coefficients from the target spectrum are compared to those from a grid of models in a Bayesian framework to determine the posterior probability distributions of the atmospheric parameters. Results. By testing our method using synthetic spectra we found that our method converges on the best fitting atmospheric parameters. We test the wavelet method on 20 FGK exoplanet host stars for which higher-quality data have been independently analysed using EW measurements. -
Arxiv:2006.10868V2 [Astro-Ph.SR] 9 Apr 2021 Spain and Institut D’Estudis Espacials De Catalunya (IEEC), C/Gran Capit`A2-4, E-08034 2 Serenelli, Weiss, Aerts Et Al
Noname manuscript No. (will be inserted by the editor) Weighing stars from birth to death: mass determination methods across the HRD Aldo Serenelli · Achim Weiss · Conny Aerts · George C. Angelou · David Baroch · Nate Bastian · Paul G. Beck · Maria Bergemann · Joachim M. Bestenlehner · Ian Czekala · Nancy Elias-Rosa · Ana Escorza · Vincent Van Eylen · Diane K. Feuillet · Davide Gandolfi · Mark Gieles · L´eoGirardi · Yveline Lebreton · Nicolas Lodieu · Marie Martig · Marcelo M. Miller Bertolami · Joey S.G. Mombarg · Juan Carlos Morales · Andr´esMoya · Benard Nsamba · KreˇsimirPavlovski · May G. Pedersen · Ignasi Ribas · Fabian R.N. Schneider · Victor Silva Aguirre · Keivan G. Stassun · Eline Tolstoy · Pier-Emmanuel Tremblay · Konstanze Zwintz Received: date / Accepted: date A. Serenelli Institute of Space Sciences (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E- 08193, Spain and Institut d'Estudis Espacials de Catalunya (IEEC), Carrer Gran Capita 2, Barcelona, E-08034, Spain E-mail: [email protected] A. Weiss Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany C. Aerts Institute of Astronomy, Department of Physics & Astronomy, KU Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium and Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands G.C. Angelou Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei M¨unchen, D-85741, Germany D. Baroch J. C. Morales I. Ribas Institute of· Space Sciences· (ICE, CSIC), Carrer de Can Magrans S/N, Bellaterra, E-08193, arXiv:2006.10868v2 [astro-ph.SR] 9 Apr 2021 Spain and Institut d'Estudis Espacials de Catalunya (IEEC), C/Gran Capit`a2-4, E-08034 2 Serenelli, Weiss, Aerts et al.