Asteroseismology of red-clump stars with CoRoT and Kepler - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado

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Abstract: The availability of asteroseismic constraints for a large number of redgiants with CoRoT and in the near future with Kepler, paves the way fordetailed studies of populations of galactic-disk red giants. We investigatewhich information on the observed population can be recovered by thedistribution of the observed seismic constraints: the frequency of maximumpower of solar-like oscillations $ u {max}$ and the large frequencyseparation $\Delta u$. We use the distribution of $ u {max}$ and of$\Delta u$ observed by CoRoT in nearly 800 red giants in the first longobservational run, as a tool to investigate the properties of galacticred-giant stars through the comparison with simulated distributions based onsynthetic stellar populations.We can clearly identify the bulk of the red giants observed by CoRoT asred-clump stars, i.e. post-flash core-He-burning stars. The distribution of$ u {max}$ and of $\Delta u$ give us access to the distribution of thestellar radius and mass, and thus represent a most promising probe of the ageand star formation rate of the disk, and of the mass-loss rate during thered-giant branch.This approach will be of great utility also in the interpretation offorthcoming surveys of variability of red giants with CoRoT and Kepler. Inparticular, an asteroseismic mass estimate of clump stars in the old-openclusters observed by Kepler, would represent a most valuable observational testof the poorly known mass-loss rate on the giant branch, and of its dependenceon metallicity.

Autor: A. Miglio, J. Montalban, P. Eggenberger, S. Hekker, A. Noels



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