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Title: A MULTIPLICITY CENSUS OF INTERMEDIATE-MASS STARS IN SCORPIUS-CENTAURUS

Stellar multiplicity properties have been studied for the lowest and the highest stellar masses, but intermediate-mass stars from F-type to late A-type have received relatively little attention. Here, we report on a Gemini/NICI snapshot imaging survey of 138 such stars in the young Scorpius-Centaurus (Sco-Cen) region, for the purpose of studying multiplicity with sensitivity down to planetary masses at wide separations. In addition to two brown dwarfs and a companion straddling the hydrogen-burning limit which we reported previously, here we present 26 new stellar companions and determine a multiplicity fraction within 0.''1-5.''0 of 21% {+-} 4%. Depending on the adopted semimajor axis distribution, our results imply a total multiplicity in the range of {approx}60%-80%, which further supports the known trend of a smooth continuous increase in the multiplicity fraction as a function of primary stellar mass. A surprising feature in the sample is a distinct lack of nearly equal-mass binaries, for which we discuss possible reasons. The survey yielded no additional companions below or near the deuterium-burning limit, implying that their frequency at >200 AU separations is not quite as high as might be inferred from previous detections of such objects within the Sco-Cen region.
Authors:
 [1] ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Astrophysical Sciences, Princeton University, Princeton, NJ (United States)
  2. Department of Physics, University of Montreal, Montreal, QC (Canada)
  3. Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON (Canada)
  4. European Southern Observatory, Santiago (Chile)
  5. Department of Astronomy, Stockholm University, Stockholm (Sweden)
  6. Department of Physics and Astronomy, University of Delaware, Newark, DE (United States)
Publication Date:
OSTI Identifier:
22130940
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DEUTERIUM; HYDROGEN BURNING; MASS; MULTIPLICITY; STARS