Volume 530, June 2011
|Number of page(s)||8|
|Section||Stellar structure and evolution|
|Published online||04 May 2011|
Long-period variables in the CoRoT fields⋆
Department of AstronomyUniversity of Vienna, Tuerkenschanzstrasse 17, 1180 Vienna, Austria
Received: 28 February 2011
Accepted: 31 March 2011
Aims. We searched the first set of data released by the CoRoT mission for red stars showing long-period variability (LPV). These stars are likely highly evolved stars on the upper giant branch. The high time resolution of the CoRoT data allows us to study the light curves of these variables in unprecedented detail.
Methods. Light curves of the reddest stars were extracted from the CoRoT public archive. The search for LPV was done by visual inspection. Instrumental artefacts were removed, and the final light curves were inspected for signs of variability on time scales of hours to a few days. Such abrupt and irregular light curve changes have been reported in the literature to occur in these stars, but their origin is not yet understood.
Results. We detected 52 LPV candidates in four CoRoT fields, most of them previously unknown. No signs of any short-time light changes on time scales between 20 min and a few days and an amplitude exceeding a few mmag could be detected. We conclude that if these short-time variations are physical reality, they must be quite rare events, and we derive a 95% confidence upper limit of 0.15 events per star per year. Any deviations from a perfectly smooth long-time variation are occurring on time scales longer than approximately 10 days.
Key words: stars: AGB and post-AGB / stars: variables: general
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.