3 juillet - 6 juillet 2018


S12 Synergie des grands surveys pour comprendre les étoiles : piliers de l’archéologie galactique

New population synthesis approach : a golden way to deep inside the Gaia-ESO giants

Lagarde, Nadège

The cornerstone mission of the European Space Agency, Gaia, together with

complementary spectroscopic (Gaia-ESO, APOGEE, LAMOST, GALAH) and seismic surveys (CoRoT, Kepler, and K2), will revolutionize our understanding of the evolution of giant stars as well as of the formation and history of our Galaxy, providing accurate stellar masses, radii, ages, distances, as well as chemical properties for very large samples of stars across different Galactic stellar populations.

To exploit all potential of the combination between spectroscopic and seismic observations, the population synthesis approach will be a very crucial and efficient tool. We develop the Besançon Galactic model (BGM, Lagarde et al 2017) for which stellar evolution predictions are included, providing the global asteroseismic properties and the surface chemical abundances along the evolution of low- and intermediate-mass stars.

Comparing synthetic populations and spectroscopic observations from Gaia-ESO survey, we investigate the effects of thermohaline mixing on carbon and nitrogen abundances using the first comparison between the Gaia-ESO survey [C/N] determinations with simulations of the observed fields using a model of stellar population synthesis (Lagarde et al 2018).