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Abstract: The detection with CoRoT of solar-like oscillations in nearly 800 red giantsin the first 150-days long observational run paves the way for detailed studiesof populations of galactic-disk red giants. We investigate which information onthe observed population can be recovered by the distribution of the observedseismic constraints: the frequency of maximum oscillation power nu max andthe large frequency separation Deltanu. We propose to use the observeddistribution of nu max and of Deltanu as a tool for investigating theproperties of galactic red-giant stars through comparison with simulateddistributions based on synthetic stellar populations. We can clearly identifythe bulk of the red giants observed by CoRoT as red-clump stars, i.e.post-flash core-He-burning stars. The distribution of nu max and of Deltanugives us access to the distribution of the stellar radius and mass, and thusrepresent a most promising probe of the age and star formation rate of thedisk, and of the mass-loss rate during the red-giant branch.CoRoT observations are supplying seismic constraints for the most populatedclass of He-burning stars in the galactic disk. This opens a new access gate toprobing the properties of red-giant stars that, coupled with classicalobservations, promises to extend our knowledge of these advanced phases ofstellar evolution and to add relevant constraints to models of compositestellar populations in the Galaxy.



Autor: A. Miglio, J. Montalban, F. Baudin, P. Eggenberger, A. Noels, S. Hekker, J. De Ridder, W. Weiss, A. Baglin

Fuente: https://arxiv.org/







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