Age dissection of the Milky Way discs: red giants in the Kepler field

Understand

[Abridged] Ensemble studies of red-giant stars with exquisite asteroseismic, spectroscopic, and astrometric constraints offer a novel opportunity to recast and address long-standing questions concerning the evolution of stars and of the Galaxy.

• Here, we infer masses and ages for nearly 5400 giants with available Kepler light curves and APOGEE spectra, and discuss some of the systematics that may affect the accuracy of the inferred stellar properties.
• First, we look at age-chemical-abundances relations.
• We find a dearth of young, metal-rich stars, and the existence of a significant population of old (8-9 Gyr), low-[$\alpha$/Fe], super-solar metallicity stars, reminiscent of the age and metallicity of the well-studied open cluster NGC6791.