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Home > Seminars > Archive of past UTINAM seminars > 2017

Nadège Lagarde

Chemical clocks of stellar populations in the Milky Way

Wednesday March 1st 2017, 14:00

Conference room of the observatory

Postdoctoral researcher at the UTINAM Institute


A broad effort is ongoing with large spectroscopic surveys such as APOGEE, Gaia-ESO, RAVE from which stellar parameters, radial velocities and detailed chemical abundances can be measured for CoRoT, Kepler, and K2 targets. In addition, asteroseismic data of red-giants stars observed by the space missions CoRoT and Kepler allow determination of stellar masses, radii, and can be used to determine the position and ages of stars. This association between spectroscopic and asteroseismic constraints provide a new way to understand galactic and stellar evolutions.

I will present the evolution of red-giant stars, computed with the stellar evolution code STAREVOL including thermohaline mixing together with rotational mixing. In Lagarde et al (2017), we developed the Besançon Galactic model (BGM) for which my stellar evolution predictions providing the global asteroseismic properties and the surface chemical abundances along the evolution of low- and intermediate-mass stars are included. For the first time, the BGM can explore the effects of an extra-mixing occurring in red-giant stars. I will present the first comparison between these synthetic populations with the significant large survey CoRoGEE (CoRoT-APOGEE).

We emphasize the usefulness of population synthesis tools to test stellar models and transport processes inside stars. We show that transport processes occurring in red-giant stars should be taken into account in the determination of ages for future Galactic archaeology studies.