SPECTROSCOPIC BINARIES IN THE ORION NEBULA CLUSTER AND NGC 2264

• Published in: The Astrophysical journal Vol. 821; no. 1; p. 8
• Main Authors: Kounkel, Marina, Hartmann, Lee, Tobin, John J., Mateo, Mario, Bailey, John I., Spencer, Meghin
• Format: Journal Article
• Language: English
• Published: United States The American Astronomical Society 10.04.2016
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; binaries: spectroscopic; BINARY STARS; Clusters; Initial fit; ISM: individual objects (ONC, NGC 2264); ISM: structure; Kinematics; MASS; MULTIPLICITY; NEBULAE; Orion nebula; Parameters; RADIAL VELOCITY; Spectroscopy; STAR CLUSTERS; STAR EVOLUTION; stars: formation
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/0004-637X/821/1/8

ABSTRACT We examine the spectroscopic binary population for two massive nearby regions of clustered star formation, the Orion Nebula Cluster (ONC) and NGC 2264, supplementing the data presented by Tobin et al. with more recent observations and more extensive analysis. The inferred multiplicity fraction up to 10 au based on these observations is 5.3 1.2% for NGC 2264 and 5.8 1.1% for the ONC; these values are consistent with the distribution of binaries in the field in the relevant parameter range. Eight of the multiple systems in the sample have enough epochs to perform an initial fit for the orbital parameters. Two of these sources are double-lined spectroscopic binaries; for them, we determine the mass ratio. Our reanalysis of the distribution of stellar radial velocities toward these clusters presents a significantly better agreement between stellar and gas kinematics than was previously thought.