Toroidal Versus Poloidal Magnetic Fields in Sun-Like Stars: a Rotation
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A&A 562, A92 (2014) Astronomy DOI: 10.1051/0004-6361/201321493 & c ESO 2014 Astrophysics Li depletion in solar analogues with exoplanets Extending the sample, E. Delgado Mena1,G.Israelian2,3, J. I. González Hernández2,3,S.G.Sousa1,2,4, A. Mortier1,4,N.C.Santos1,4, V. Zh. Adibekyan1, J. Fernandes5, R. Rebolo2,3,6,S.Udry7, and M. Mayor7 1 Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [email protected] 2 Instituto de Astrofísica de Canarias, C/ Via Lactea s/n, 38200 La Laguna, Tenerife, Spain 3 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 4 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal 5 CGUC, Department of Mathematics and Astronomical Observatory, University of Coimbra, 3049 Coimbra, Portugal 6 Consejo Superior de Investigaciones Científicas, CSIC, Spain 7 Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland Received 18 March 2013 / Accepted 25 November 2013 ABSTRACT Aims. We want to study the effects of the formation of planets and planetary systems on the atmospheric Li abundance of planet host stars. Methods. In this work we present new determinations of lithium abundances for 326 main sequence stars with and without planets in the Teff range 5600–5900 K. The 277 stars come from the HARPS sample, the remaining targets were observed with a variety of high-resolution spectrographs. Results. We confirm significant differences in the Li distribution of solar twins (Teff = T ± 80 K, log g = log g ± 0.2and[Fe/H] = [Fe/H] ±0.2): the full sample of planet host stars (22) shows Li average values lower than “single” stars with no detected planets (60). -
Predictions for the Secondary CO, C and O Gas Content of Debris Discs from the Destruction of Volatile-Rich Planetesimals
Mon. Not. R. Astron. Soc. 000, 1{27 (2002) Printed 3 April 2017 (MN LATEX style file v2.2) Predictions for the secondary CO, C and O gas content of debris discs from the destruction of volatile-rich planetesimals Quentin Kral?, Luca Matr`a,Mark C. Wyatt, Grant M. Kennedy Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK Accepted 1928 December 15. Received 1928 December 14; in original form 1928 October 11 ABSTRACT This paper uses observations of dusty debris discs, including a growing number of gas detections in these systems, to test our understanding of the origin and evolution of this gaseous component. It is assumed that all debris discs with icy planetesimals create second generation CO, C and O gas at some level, and the aim of this paper is to predict that level and assess its observability. We present a new semi-analytical equivalent of the numerical model of Kral et al. (2016) allowing application to large numbers of systems. That model assumes CO is produced from volatile-rich solid bodies at a rate that can be predicted from the debris discs fractional luminosity. CO photodissociates rapidly into C and O that then evolve by viscous spreading. This model provides a good qualitative explanation of all current observations, with a few exceptional systems that likely have primordial gas. The radial location of the debris and stellar luminosity explain some non-detections, e.g. close-in debris (like HD 172555) is too warm to retain CO, while high stellar luminosities (like η Tel) result in short CO lifetimes. -
Asteroseismology of Solar-Type Stars
Living Reviews in Solar Physics (2019) 16:4 https://doi.org/10.1007/s41116-019-0020-1 REVIEW ARTICLE Asteroseismology of solar-type stars Rafael A. García1,2 · Jérôme Ballot3 Received: 29 August 2018 / Accepted: 19 June 2019 / Published online: 9 September 2019 © The Author(s) 2019 Abstract Until the last few decades, investigations of stellar interiors had been restricted to theoretical studies only constrained by observations of their global properties and external characteristics. However, in the last 30years the field has been revolutionized by the ability to perform seismic investigations of stellar interiors. This revolution begun with the Sun, where helioseismology has been yielding information competing with what can be inferred about the Earth’s interior from geoseismology. The last two decades have witnessed the advent of asteroseismology of solar-like stars, thanks to a dramatic development of new observing facilities providing the first reliable results on the interiors of distant stars. The coming years will see a huge development in this field. In this review we focus on solar-type stars, i.e., cool main-sequence stars where oscillations are stochastically excited by surface convection. After a short introduction and a historical overview of the discipline, we review the observational techniques generally used, and we describe the theory behind stellar oscillations in cool main- sequence stars. We continue with a complete description of the normal mode analyses through which it is possible to extract the physical information about the structure and dynamics of the stars. We then summarize the lessons that we have learned and discuss unsolved issues and questions that are still unanswered. -
A Photometric and Spectroscopic Survey of Solar Twin Stars Within 50
Astronomy & Astrophysics manuscript no. Porto-de-Mello-et-al-Solar-Twin-Survey˙PREPRINT c ESO 2018 July 7, 2018 A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun: I. Atmospheric parameters and color similarity to the Sun G. F. Porto de Mello1, R. da Silva1,⋆, L. da Silva2 and R. V. de Nader1,⋆⋆ 1 Universidade Federal do Rio de Janeiro, Observat´orio do Valongo, Ladeira do Pedro Antonio 43, CEP: 20080-090 Rio de Janeiro, RJ, Brazil e-mail: [email protected],[email protected],[email protected] 2 Observat´orio Nacional, Rua Gen. Jos´eCristino 77, CEP: 20921-400, Rio de Janeiro, Brazil e-mail: [email protected] Received; accepted ABSTRACT Context. Solar twins and analogs are fundamental in the characterization of the Sun’s place in the context of stellar measurements, as they are in understanding how typical the solar properties are in its neighborhood. They are also important for representing sunlight observable in the night sky for diverse photometric and spectroscopic tasks, besides being natural candidates for harboring planetary systems similar to ours and possibly even life-bearing environments. Aims. We report a photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun. Hipparcos absolute mag- nitudes and (B V)Tycho colors were used to define a 2σ box around the solar values, where 133 stars were considered. Additional stars resembling− the solar UBV colors in a broad sense, plus stars present in the lists of Hardorp, were also selected. All objects were ranked by a color-similarity index with respect to the Sun, defined by uvby and BV photometry. -
Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: a Survey of Stellar and Planetary Companions Within 25 Pc
Draft version December 18, 2020 Typeset using LATEX twocolumn style in AASTeX62 Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc Lea A. Hirsch,1 Lee Rosenthal,2 Benjamin J. Fulton,3 Andrew W. Howard,2 David R. Ciardi,4 Geoffrey W. Marcy,5 Eric L. Nielsen,6, 1 Erik A. Petigura,7 Robert J. de Rosa,8, 1 Howard Isaacson,5 Lauren M. Weiss,9 Evan Sinukoff,9 and Bruce Macintosh1 1Kavli Center for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA 2California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA 3NASA Exoplanet Science Institute, Caltech/IPAC-NExScI, 1200 East California Boulevard, Pasadena, CA 91125, USA 4NASA Exoplanet Science Institute, Caltech/IPAC, 1200 East California Boulevard, Pasadena, CA 91125, USA 5University of California Berkeley, 501 Campbell Hall, Berkeley, CA 94709, USA 6Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003, USA 7Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA 8European Southern Observatory, Alonso de C´ordova 3107, Vitacura, Santiago, Chile 9Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822, USA (Accepted December 7, 2020) Submitted to AJ ABSTRACT We explore the impact of outer stellar companions on the occurrence rate of giant planets detected with radial velocities. We searched for stellar and planetary companions to a volume-limited sample of solar-type stars within 25 pc. Using adaptive optics (AO) imaging observations from the Lick 3-m and Palomar 20000 Telescopes, we characterized the multiplicity of our sample stars, down to the bottom of the main sequence. -
Beryllium Abundances in Stars with Planets Extending the Sample
A&A 530, A66 (2011) Astronomy DOI: 10.1051/0004-6361/200913827 & c ESO 2011 Astrophysics Beryllium abundances in stars with planets Extending the sample M. C. Gálvez-Ortiz1, E. Delgado-Mena2, J. I. González Hernández2,3, G. Israelian2,N.C.Santos4, R. Rebolo2,5, and A. Ecuvillon2 1 Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, HatfieldAL109AB,UK e-mail: [email protected] 2 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain 3 Dpto. de Astrofísica y Ciencias de la Atmósfera, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain 4 Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 5 Consejo Superior de Investigaciones Científicas, Spain Received 8 December 2009 / Accepted 31 March 2011 ABSTRACT Context. Chemical abundances of light elements such as beryllium in planet-host stars allow us to study the planet formation scenarios and/or investigate possible surface pollution processes. Aims. We present here an extension of previous beryllium abundance studies. The complete sample consists of 70 stars that host planets and 30 stars without known planetary companions. The aim of this paper is to further assess the trends found in previous studies with fewer objects. This will provide more information on the processes of depletion and mixing of light elements in the interior of late-type stars, and will provide possible explanations for the abundance differences between stars that host planets and “single” stars. Methods. Using high-resolution UVES spectra, we measure beryllium abundances of 26 stars that host planets and one “single” star mainly using the λ 3131.065 Å Be ii line, by fitting synthetic spectra to the observational data. -
Arxiv:1207.6212V2 [Astro-Ph.GA] 1 Aug 2012
Draft: Submitted to ApJ Supp. A Preprint typeset using LTEX style emulateapj v. 5/2/11 PRECISE RADIAL VELOCITIES OF 2046 NEARBY FGKM STARS AND 131 STANDARDS1 Carly Chubak2, Geoffrey W. Marcy2, Debra A. Fischer5, Andrew W. Howard2,3, Howard Isaacson2, John Asher Johnson4, Jason T. Wright6,7 (Received; Accepted) Draft: Submitted to ApJ Supp. ABSTRACT We present radial velocities with an accuracy of 0.1 km s−1 for 2046 stars of spectral type F,G,K, and M, based on ∼29000 spectra taken with the Keck I telescope. We also present 131 FGKM standard stars, all of which exhibit constant radial velocity for at least 10 years, with an RMS less than 0.03 km s−1. All velocities are measured relative to the solar system barycenter. Spectra of the Sun and of asteroids pin the zero-point of our velocities, yielding a velocity accuracy of 0.01 km s−1for G2V stars. This velocity zero-point agrees within 0.01 km s−1 with the zero-points carefully determined by Nidever et al. (2002) and Latham et al. (2002). For reference we compute the differences in velocity zero-points between our velocities and standard stars of the IAU, the Harvard-Smithsonian Center for Astrophysics, and l’Observatoire de Geneve, finding agreement with all of them at the level of 0.1 km s−1. But our radial velocities (and those of all other groups) contain no corrections for convective blueshift or gravitational redshifts (except for G2V stars), leaving them vulnerable to systematic errors of ∼0.2 km s−1 for K dwarfs and ∼0.3 km s−1 for M dwarfs due to subphotospheric convection, for which we offer velocity corrections. -
On the Mass Estimation for FGK Stars: Comparison of Several Methods
Mon. Not. R. Astron. Soc. 000, 1–?? (2002) Printed 29 August 2014 (MN LATEX style file v2.2) On the mass estimation for FGK stars: comparison of several methods F. J. G. Pinheiro1,2⋆, J. M. Fernandes1,2,3, M. S. Cunha4,5, M. J. P. F. G. Monteiro4,5,6, N. C. Santos4,5,6, S. G. Sousa4,5,6, J. P. Marques7, J.-J. Fang8, A. Mortier9 and J. Sousa4,5 1Centro de Geofísica da Universidade de Coimbra 2Observatório Geofísico e Astronómico da Universidade de Coimbra 3Departamento de Matemática da Universidade de Coimbra, Largo D. Dinis, P-3001-454 Coimbra, Portugal 4Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal 5Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 6Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal 7The Institut d’Astrophysique Spatiale, Orsay, France 8Centro de Física Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra, Portugal 9SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK Accepted . Received ABSTRACT Stellar evolutionary models simulate well binary stars when individual stellar mass and system metallicity are known. The mass can be derived directly from observations only in the case of multiple stellar systems, mainly binaries. Yet the number of such stars for which ls accurate stellar masses are available is rather small. The main goal of this project is to provide realistic mass estimates for an homogeneous sample of about a thousand FGK single stars, using four different methods and techniques. -
Copyright by Kevin Carl Gullikson 2016 the Dissertation Committee for Kevin Carl Gullikson Certifies That This Is the Approved Version of the Following Dissertation
Copyright by Kevin Carl Gullikson 2016 The Dissertation Committee for Kevin Carl Gullikson certifies that this is the approved version of the following dissertation: Spectroscopic Detection and Characterization of Extreme Flux-Ratio Binary Systems Committee: Adam Kraus, Supervisor Sarah Dodson-Robinson Daniel T. Jaffe Edward L. Robinson Michael Meyer Spectroscopic Detection and Characterization of Extreme Flux-Ratio Binary Systems by Kevin Carl Gullikson, B.S; M.A. Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy The University of Texas at Austin May, 2016 Dedicated to my loving parents, who encouraged my exploration of science from an early age. Acknowledgements I would like to start by thanking everyone who served as a supervisor during part of my thesis. Mike Endl served as my co-supervisor for two years, taught me how to observe on the 2.7m telescope at McDonald observatory, and involved me in the planet search program for the last 5 years. That experience provided many interesting nights, a fun "side project", and gave me the confidence to do much of the observing for my main survey program. Sally Dodson-Robinson served as my thesis supervisor for my first two years. She gave me a great deal of independence in my project, while providing valuable feedback. I would like to thank both her and my current supervisor, Adam Kraus, for nominating me for several UT fellowships and funding me as a research assistant during much of my graduate career. -
A Near-Infrared Interferometric Survey of Debris-Disk Stars VII
Astronomy & Astrophysics manuscript no. PIONIER_exozodi20_final ©ESO 2021 April 30, 2021 A near-infrared interferometric survey of debris-disk stars VII. The hot/warm dust connection? O. Absil1,??, L. Marion1, S. Ertel2; 3, D. Defrère4, G. M. Kennedy5, A. Romagnolo6, J.-B. Le Bouquin7, V. Christiaens8, J. Milli7, A. Bonsor9, J. Olofsson10; 11, K. Y. L. Su3, and J.-C. Augereau7 1 STAR Institute, Université de Liège, 19c Allée du Six Août, 4000 Liège, Belgium 2 Large Binocular Telescope Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA 3 Steward Observatory, Department of Astronomy, University of Arizona, 993 N. Cherry Ave, Tucson, AZ, 85721, USA 4 Institute of Astronomy, KU Leuven, Celestijnlaan 200D, 3001 Leuven, Belgium 5 Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK 6 Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716, Warsaw, Poland 7 Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France 8 School of Physics and Astronomy, Monash University, Clayton, Vic 3800, Australia 9 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 10 Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Val- paraíso, Chile 11 Núcleo Milenio Formación Planetaria - NPF, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso, Chile Received 6 June 2017; accepted 21 April 2021 ABSTRACT Context. Hot exozodiacal dust has been shown to be present in the innermost regions of an increasing number of main sequence stars over the past fifteen years. The origin of hot exozodiacal dust and its connection with outer dust reservoirs remains however unclear. -
Properties of Members of Stellar Kinematic Groups and Stars with Circumstellar Dusty Debris Discs
UNIVERSIDAD AUTONOMA´ DE MADRID Facultad de Ciencias Departamento de F´ısica Teorica´ A spectroscopic study of the nearby late-type stellar population: Properties of members of stellar kinematic groups and stars with circumstellar dusty debris discs. PhD dissertation submitted by Jesus´ Maldonado Prado for the degree of Doctor in Physics Supervised by Dr. Carlos Eiroa de San Francisco Madrid, June 2012 UNIVERSIDAD AUTONOMA´ DE MADRID Facultad de Ciencias Departamento de F´ısica Teorica´ Estudio espectroscopico´ de la poblacion´ estelar fr´ıa cercana: Propiedades de estrellas en grupos cinematicos´ estelares y de estrellas con discos circunestelares de tipo debris. Memoria de tesis doctoral presentada por Jesus´ Maldonado Prado para optar al grado de Doctor en Ciencias F´ısicas Trabajo dirigido por el Dr. Carlos Eiroa de San Francisco Madrid, Junio de 2012 A mis padres y hermanos Agradecimientos La finalizaci´on de una tesis doctoral es siempre un momento para el balance y la reflexi´on. Conf´ıo que estas breves palabras sirvan de peque˜no reconocimiento a todas las personas que durante todo este largo, y no siempre f´acil, per´ıodo de tiempo han tenido a bien brindarme su ayuda, su apoyo y, en muchos casos, su simpat´ıa. A todos los que de alguna manera me habe´ıs ayudado, gracias. Las primeras palabras de estas notas deben ser para mi supervisor de tesis, Carlos Eiroa, por su confianza, su apoyo y dedicaci´on y sobre todo por esa mi- rada cr´ıtica tan suya que, desde siempre, ha tratado de transmitirme. A Benjam´ın Montesinos debo agradecerle muchas cosas, en particular su cercan´ıa y su forma de ser, a David Montes y a Raquel Mart´ınez, su esfuerzo y dedicaci´on. -
The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems
UvA-DARE (Digital Academic Repository) The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems Janson, M.; et al., [Unknown]; Thalmann, C. DOI 10.1088/0004-637X/773/1/73 Publication date 2013 Document Version Final published version Published in Astrophysical Journal Link to publication Citation for published version (APA): Janson, M., et al., U., & Thalmann, C. (2013). The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems. Astrophysical Journal, 773(1), 73. https://doi.org/10.1088/0004-637X/773/1/73 General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:26 Sep 2021 The Astrophysical Journal, 773:73 (11pp), 2013 August 10 doi:10.1088/0004-637X/773/1/73 C 2013.