Volume 537, January 2012
|Number of page(s)||6|
|Section||Stellar structure and evolution|
|Published online||23 January 2012|
Oscillation mode linewidths of main-sequence and subgiant stars observed by Kepler
1 Université Paris-Sud, Institut d’Astrophysique Spatiale, UMR8617, CNRS, Bâtiment 121, 91405 Orsay Cedex, France
2 Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106-4030, USA
3 Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, New South Wales 2006, Australia
4 Department of Astronomy & Physics, Saint Mary’s University, Halifax, NS B3H 3C3, Canada
5 School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
6 Laboratoire AIM, CEA/DSM–CNRS–Université Paris Diderot, IRFU/SAp, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
7 Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8 Aarhus C, Denmark
8 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 45, India
9 Centro de Astrofísica, DFA-Faculdade de Ciências, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
10 Department of Astronomy, Yale University, PO Box 208101, New Haven CT 06520-8101, USA
11 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
12 Université de Nice Sophia-Antipolis, CNRS UMR 6202, Observatoire de la Côte d’Azur, BP 4229, 06304 Nice Cedex 4, France
13 Institute of Astronomy, University of Vienna, 1180 Vienna, Austria
14 Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, 85748 Garching bei München, Germany
15 SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035, USA
16 Orbital Sciences Corporation/NASA Ames Research Center, Moffett Field, CA 94035, USA
Received: 22 November 2011
Accepted: 13 December 2011
Context. Solar-like oscillations have been observed by Kepler and CoRoT in several solar-type stars.
Aims. We study the variations in the stellar p-mode linewidth as a function of effective temperature.
Methods. We study a time series of nine months of Kepler data. We analyse the power spectra of 42 cool main-sequence stars and subgiants using both maximum likelihood estimators and Bayesian estimators to recover individual mode characteristics such as frequencies, linewidths, and mode heights.
Results. We report on the mode linewidth at both maximum power and maximum mode height for these 42 stars as a function of effective temperature.
Conclusions. We show that the mode linewidth at either maximum mode height or maximum amplitude follows a scaling relation with effective temperature, which is a combination of a power law and a lower bound. The typical power-law index is about 13 for the linewidth derived from the maximum mode height, and about 16 for the linewidth derived from the maximum amplitude, while the lower bound is about 0.3 μHz and 0.7 μHz, respectively. We stress that this scaling relation is only valid for cool main-sequence stars and subgiants, and does not have any predictive power outside the temperature range of these stars.
Key words: methods: data analysis / asteroseismology / stars: solar-type
© ESO, 2012
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