Radial mode widths in red giant stars spectra observed by Kepler

¹ Instituto de Astrofísica e Ciências do EspaÇo, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762, Porto, Portugal
² LESIA, CNRS, PSL Research University, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon cedex, France

^⋆ e-mail: mathieu.vrard@astro.up.pt

Published online: 27 October 2017

Abstract

The Kepler space mission has observed many solar-like pulsators, and helped to decipher their fundamental parameters (e.g: mass, radius, rotation). Most of the achievements recently obtained in that domain result from the analysis of the mode frequencies. However, unique information on non-adiabatic physics derives from the height and width of the modes. In this study, we aim at measuring the mode widths of the pressure modes in thousands of Kepler red giants and to analyze their variations in function of stellar parameters. To achieve that, we used a peakbagging technique on the star radial modes. The results show a relation between the radial mode linewidth and the effective temperature of the star as theoretically predicted. We also unveil a clear dependence with mass and stellar evolution for the radial mode width. This means that the mode damping depends on the evolutionary status of the stars.