2013ApJ...773..170J -
Astrophys. J., 773, 170 (2013/August-3)
A multiplicity census of intermediate-mass stars in Scorpius-Centaurus.
JANSON M., LAFRENIERE D., JAYAWARDHANA R., BONAVITA M., GIRARD J.H., BRANDEKER A. and GIZIS J.E.
Abstract (from CDS):
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 ∼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.
Abstract Copyright:
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Journal keyword(s):
binaries: general - brown dwarfs - planetary systems
Simbad objects:
157
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