Chemical abundances from APOGEE. II. M67 stars

The sample contains stars spanning a wide range of evolutionary phases, from G dwarfs to red clump stars. The abundances were derived from near-IR ({lambda}1.5-1.7{mu}m) high-resolution spectra (R=22500) from the SDSS-IV/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey.

A 1D local thermodynamic equilibrium abundance analysis was carried out using the APOGEE synthetic spectral libraries, via {chi}^2^ minimization of the synthetic and observed spectra with the qASPCAP code. We found significant abundance differences (~0.05-0.30dex) between the M67 member stars as a function of the stellar mass (or position on the Hertzsprung-Russell diagram), where the abundance patterns exhibit a general depletion (in [X/H]) in stars at the main-sequence turnoff.