2013/03/29 by M. S. Oey, J. B. Lamb, C. T. Kushner +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Field (mathematics) #Large Magellanic Cloud #O-type star #Projection (relational algebra) #Sample (material) #Star cluster #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1088/0004-637x/768/1/66
Accepted to ApJ, 12 pages
arxiv created 2013/03/29 · openalex publication_date 2013/04/16 · arxiv updated 2015/06/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a sample of 14 OB stars in the Small Magellanic Cloud that meet strong criteria for having formed under extremely sparse star-forming conditions in the field. These stars are a minimum of 28 pc in projection from other OB stars, and they are centered within symmetric, round H ii regions. They show no evidence of bow shocks, implying that the targets are not transverse runaway stars. Their radial velocities relative to local H i also indicate that they are not line-of-sight runaway stars. A friends-of-friends analysis shows that nine of the objects present a few low-mass companion stars, with typical mass ratios for the two highest-mass stars of around 0.1. This further substantiates that these OB stars formed in place, and that they can and do form in extremely sparse conditions. This poses strong constraints on theories of star formation and challenges proposed relations between cluster mass and maximum stellar mass.