LMI and LDT observation of Berkeley 50 members

We obtained UBV photometry of 1145 stars in a 12.3x12.3' field, and used Gaia proper motions and parallaxes to identify 64 members, of which we obtained spectra of the 17 brightest members. The majority of the observed population we classified as Bdwarfs, with the exception of a newly identified red supergiant star, which our spectroscopy shows has a B-type companion.

Our study establishes the distance as 3.8kpc, with an average color-excess E(B-V)=0.9. Comparison of the physical properties of the cluster with the Geneva evolutionary tracks places the age of the cluster as 50-60Myr, with its most massive members being ~7M{sun}.