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Amplitudes and lifetimes of solar-like oscillations observed by CoRoT Red-giant versus main-sequence stars

TitreAmplitudes and lifetimes of solar-like oscillations observed by CoRoT Red-giant versus main-sequence stars
Type de publicationJournal Article
Year of Publication2011
AuteursBaudin, F, Barban, C, Belkacem, K, Hekker, S, Morel, T, Samadi, R, Benomar, O, Goupil, MJ, Carrier, F, Ballot, J, Deheuvels, S, De Ridder, J, Hatzes, AP, Kallinger, T, Weiss, WW
JournalAstronomy & Astrophysics
Date PublishedMay
ISBN Number0004-6361
Numéro d'accèsWOS:000289557200092

Context. The advent of space-borne missions such as CoRoT or Kepler providing photometric data has brought new possibilities for asteroseismology across the H-R diagram. Solar-like oscillations are now observed in many stars, including red giants and main-sequence stars. Aims. Based on several hundred identified pulsating red giants, we aim to characterize their oscillation amplitudes and widths. These observables are compared with those of main-sequence stars in order to test trends and scaling laws for these parameters for main-sequence stars and red giants. Methods. An automated fitting procedure is used to analyze several hundred Fourier spectra. For each star, a modeled spectrum is fitted to the observed oscillation spectrum, and mode parameters are derived. Results. Amplitudes and widths of red-giant solar-like oscillations are estimated for several hundred modes of oscillation. Amplitudes are relatively high (several hundred ppm) and widths relatively small (very few tenths of a mu Hz). Conclusions. Widths measured in main-sequence stars show a different variation with the effective temperature from red giants. A single scaling law is derived for mode amplitudes of red giants and main-sequence stars versus their luminosity to mass ratio. However, our results suggest that two regimes may also be compatible with the observations.

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