Gaia-ESO Survey: Massive stars in the Carina Nebula. I. A new census of OB stars
/ Authors
S. R. Berlanas, J. M. Apell'aniz, A. Herrero, L. Mahy, R. Blomme, I. Negueruela, R. Dorda, F. Comer'on, E. Gosset, M. Gonz'alez
and 9 more authors
J. M. Lera, A. Sota, T. Furst, E. Alfaro, M. Bergemann, G. Carraro, J. Drew, L. Morbidelli, J. Vink
/ Abstract
The Gaia-ESO survey sample of massive OB stars in the Carina Nebula consists of 234 stars. The addition of brighter sources from the Galactic O-Star Spectroscopic Survey and additional sources from the literature allows us to create the most complete census of massive OB stars done so far in the region. It contains a total of 316 stars, being 18 of them in the background and four in the foreground. Of the 294 stellar systems in Car OB1, 74 are of O type, 214 are of non-supergiant B type and 6 are of WR or non-O supergiant (II to Ia) spectral class. We identify 20 spectroscopic binary systems with an O-star primary, of which 6 are reported for the first time, and another 18 with a B-star primary, of which 13 are new detections. The average observed double-lined binary fraction of O-type stars in the surveyed region is 0.35, which represents a lower limit. We find a good correlation between the spectroscopic n-qualifier and the projected rotational velocity of the stars. The fraction of candidate runaways among the stars with and without the n-qualifier is 4.4% and 2.4%, respectively, although non resolved double-lined binaries can be contaminating the fast rotators sample.
Journal: Astronomy & Astrophysics