Bibcode
Ahmic, Mirza; Jayawardhana, R.; Brandeker, A.; Scholz, A.; van Kerkwijk, M. H.; Delgado-Donate, E.; Froebrich, D.
Bibliographical reference
2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, #40.06; Bulletin of the American Astronomical Society, Vol. 39, p.265
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5
2007
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Description
Characterizing multiplicity in the very low mass (VLM) domain is a topic
of much current interest and fundamental importance. Here we report on a
near-infrared adaptive optics imaging survey of 28 young brown dwarfs
and VLM stars, 26 of which are in the Chamaeleon I star-forming region,
using the ESO Very Large Telescope. Our findings in Cha I -- the low
multiplicity frequency of 8%, the preference for equal mass pairs, and
the lack of wide binaries -- are strikingly similar to what has
previously been reported for VLM objects in the field and in open
clusters. Thus, we argue that there is no significant evolution of
multiplicity with age among brown dwarfs and VLM stars between a few Myr
to several Gyr. Instead, the observations to date suggest that VLM
objects are either less likely to be born in wide multiple systems than
solar mass stars or such systems are disrupted very early (within the
first couple of Myr). Our results also imply that systems like 2MASSW
J1207334-393254 and Oph 162225-240515, with planetary mass companions at
wide separations, are rare.
This research was supported by an NSERC grant, University of Toronto
research funds and the Ontario Graduate Scholarship.