The G305 Star-Forming Region. I. Newly Classified Hot Stars

Abstract The relatively nearby star-forming complex G305 is one of the most luminous H ii regions in the Galaxy, and it contains several sites and epochs of star formation. Using a combination of near-infrared photometry from “Vista Variables in Via Lactea” ESO Large Public Survey, SDSS-IV APOGEE-2 spectra, and Gaia DR2 photometry and astrometry, we report on 29 OB type, Wolf–Rayet, and emission-line stars, 18 of which are newly classified. Most of these hot stars belongs to the main sequence, although some stars of class I are also proposed. The mean radial velocity is RV = −41.8 <?CDATA $\mathrm{km}\,{{\rm{s}}}^{-1}$?> . The average spectroscopic distance is 3.2 ± 1.6 kpc, while the Gaia DR2 average distance is 3.7 ± 1.8 kpc. Eight objects show light-curve variations with amplitudes greater than 0.5 mag in the K S band.