Kratter, Kaitlin M.
Stassun, Keivan G.
Kim, Jinyoung Serena
Ramírez, Karla Peña
Stringfellow, Guy S
Jaehnig, Karl O
Maqueo Chew, Yilen Gómez
Nidever, David L.
De Lee, Nathan
AffiliationUniv Arizona, Steward Observ
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PublisherIOP PUBLISHING LTD
CitationMarina Kounkel et al 2019 AJ 157 196
RightsCopyright © 2019. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractMultiplicity is a fundamental property that is set early during stellar lifetimes, and it is a stringent probe of the physics of star formation. The distribution of close companions around young stars is still poorly constrained by observations. We present an analysis of stellar multiplicity derived from Apache Point Observatory Galactic Evolution Experiment-2 spectra obtained in targeted observations of nearby star-forming regions. This is the largest homogeneously observed sample of high-resolution spectra of young stars. We developed an autonomous method to identify double-lined spectroscopic binaries (SB2s). Out of 5007 sources spanning the mass range of similar to 0.05-1.5 M-circle dot, we find 399 binaries, including both radial velocity (RV) variables and SB2s. The mass ratio distribution of SB2s is consistent with being uniform for q < 0.95 with an excess of twins for q > 0.95. The period distribution is consistent with what has been observed in close binaries (< 10 au) in the evolved populations. Three systems are found to have q similar to 0.1, with a companion located within the brown dwarf desert. There are no strong trends in the multiplicity fraction as a function of cluster age from 1 to 100 Myr. There is a weak dependence on stellar density, with companions being most numerous at Sigma(*) similar to 30 stars/pc(-2) and decreasing in more diffuse regions. Finally, disk-bearing sources are deficient in SB2s (but not RV variables) by a factor of similar to 2; this deficit is recovered by the systems without disks. This may indicate a quick dispersal of disk material in shortperiod equal-mass systems that is less effective in binaries with lower q.
VersionFinal published version
SponsorsNSF [AST-1449476]; Research Corporation via a Time Domain Astrophysics Scialog award ; NASA [ATP-170070]; program UNAM-DGAPA-PAPIIT [IN 108117]; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) through the FONDECYT ; QUIMAL project ; CONICYT PAI Concurso Nacional de Insercion en la Academia [2016 Folio PAI79160052]; Ministry for the Economy, Development and Tourism, Programa Iniciativa Cientica Milenio grant [IC120009]; Alfred P. Sloan Foundation; U.S. Department of Energy Office of Science; Center for High Performance Computing at the University of Utah; Carnegie Institution for Science; Chilean Participation Group; French Participation Group; Harvard-Smithsonian Center for Astrophysics; Johns Hopkins University; Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo; Max-Planck-Institut fur Astrophysik (MPA Garching); Max-Planck-Institut fur Extraterrestrische Physik (MPE); New Mexico State University, New York University, University of Notre Dame, Observatario Nacional/MCTI; Shanghai Astronomical Observatory, United Kingdom Participation Group; Yale University