The G305 Star-forming Region. I. Newly Classified Hot Stars
Kounkel, Marina; Minniti, Dante; Stringfellow, Guy; Covey, Kevin; Barbá, Rodolfo H.; Suárez, Genaro; Kuhn, M. A.; Roman-Lopes, Alexandre; Borissova, Jura; Lucas, Philip; Contreras Peña, Carlos; Medina, Nicolas; Kurtev, Radostin; Roman-Zuniga, Carlos; Ramirez Alegria, Sebastian
Chile, United States, Mexico, United Kingdom, Vatican City
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 {km} {{{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.
Based on Vista Variables in the Vía Láctea (VVV); SDSS-IV APOGEE-2 and Gaia DR2 data.