Metallicities of Coma Berenices bona fide members

Metallicities were determined using the high-resolution (R={lambda}/{Delta}{lambda}~22500) NIR spectra ({lambda}1.51-{lambda}1.69{mu}m) of the Sloan Digital Sky Survey IV APOGEE survey. Membership to the cluster was confirmed using previous studies in the literature along with APOGEE radial velocities and GaiaDR2.

An LTE analysis using plane-parallel MARCS model atmospheres and the APOGEE DR16 line list was adopted to compute synthetic spectra and derive atmospheric parameters (Teff and logg) for the M dwarfs and metallicities for the sample. The derived metallicities are near-solar and are homogeneous at the level of the expected uncertainties, in particular when considering stars from a given stellar class. The mean metallicity computed for the sample of G, K, and M dwarfs is <[Fe/H]>=+0.04+/-0.02dex; however, the metallicities of the F-type stars are slightly lower, by about 0.04dex, when compared to cooler and less massive members.