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

Markus Janson*, David Lafreniere, Ray Jayawardhana, Mariangela Bonavita, Julien H. Girard, Alexis Brandeker, John E. Gizis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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 similar to 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.

Original languageEnglish
Article number170
Number of pages15
JournalAstrophysical Journal
Volume773
Issue number2
DOIs
Publication statusPublished - 20 Aug 2013

Keywords

  • binaries: general
  • brown dwarfs
  • planetary systems
  • YOUNG SOLAR ANALOG
  • CIRCLE-DOT STARS
  • BROWN DWARFS
  • EVOLUTIONARY MODELS
  • SPITZER MIPS
  • HR 8799
  • COMPANIONS
  • SPECTROSCOPY
  • ASSOCIATION
  • ATMOSPHERES

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