Study of solar neighborhood open cluster NGC 6475 and 11 possible members B-type stars

Abstract

In the present paper, we performed the optical, astrometric and spectroscopic studies for the open star cluster NGC 6475 using Gaia DR3 data. Using the radial density profile, we estimated the radius of the cluster to be equal to 1.44°. It is located at a distance of 279 ± 17 pc and has a service life of 224 ± 26 Myr. The mean proper motions in RA are 268.50 ± 0.80 mas yr⁻¹ and in DEC, they are −34.83 ± 0.70 mas yr⁻¹. Using spectroscopic radial velocity data of Gaia DR3, the median radial velocity is −14.47 ± 1.92 km s⁻¹. We determined the physical parameters (T_eff, log g and V sin i) for 11 possible members of the B-type stars in the open cluster NGC 6475, using the Barbier–Chalonge–Divan (BCD) spectrophotometry system. We also determined the projected rotational velocity of the stars by matching them with the theoretical LTE model and located our studied stars over the HR diagram. From the 11 studied B-type stars, we found six members from them.