Age-metallicity relation in solar vicinity from RGB stars

In this study, the age-metallicity relation for evolved stars in the solar vicinity is investigated by using spectroscopic and astrometric data of red giant branch stars (RGB). Spectroscopic data are provided from SDSS IV APOGEE DR14 catalogue and complemented with Gaia DR2 astrometric data. Sample stars are selected by constraining the effective temperature (Teff) and surface gravity (log g) with the following constraints, 3550 ≤ Teff (K) ≤ 5600 and 0.5 ≤ log g (cm s−2) ≤ 3.5, respectively. Furthermore, additional constraint are applied on the relative parallax errors (σπ/π ≤ 0.1) and total space velocity errors (Serr ≤ 9.2 km s−1), leaving 62928 stars to study. Moreover, RGB sample is constraint based on the distance to Galactic center (Rgc), α and Fe abundances, and distance to Galactic plane (z) of the stars in order to investigate the age-metallicity relation. Analyses show a significant change in metallicity with age for the thin and thick discs RGB stars.