Oscillation mode lifetimes of red giants observed during the initial and first anticentre long run of CoRoT
- Author(s)
- S. Hekker, C. Barban, F. Baudin, J. De Ridder, T. Kallinger, T. Morel, W. J. Chaplin, Y. Elsworth
- Abstract
Context. Long time series of data increase the frequency resolution in the power spectrum. This allows for resolving stochastically excited modes with long mode lifetimes, as well as features that are close together in frequency. The CoRoT fields observed during the initial run and second long run partly overlap, and stars in this overlapping field observed in both runs are used to create time series with a longer timespan than available from the individual runs. Aims: We aim to measure the mode lifetimes of red giants and compare them with theoretical predictions. We also investigate the dependence of the mode lifetimes on frequency and the degree of the oscillation modes. Methods: We perform simulations to investigate the influence of the gap in the data between the initial and second long run, the total length of the run and the signal-to-noise ratio on the measured mode lifetime.This provides us with a correction factor to apply to the mode lifetimes measured from a maximum likelihood fit to the oscillation frequencies. Results: We find that the length of the time series, the signal-to-noise ratio and possible gaps do have a non-negligible effect on the measurements of the mode lifetime of stochastically excited oscillation modes, but we can correct for it. For the four stars for which we can perform a fit of the oscillation frequencies, we find that the mode lifetimes depend on frequency and on degree of the mode, which quantitatively agrees with theoretical predictions.The CoRoT space mission which was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. Light curves can be retrieved from the CoRoT archive: idoc-corot.ias.u-psud.fr.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- University of Birmingham, Katholieke Universiteit Leuven, Université de recherche Paris Sciences et Lettres, Université Paris XI - Paris-Sud, University of British Columbia (UBC), Université de Liège
- Journal
- Astronomy & Astrophysics
- Volume
- 520
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361/201014944
- Publication date
- 09-2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103004 Astrophysics
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/17e6d5df-9028-49dd-8a62-159df3e882f1