Cool Stars 14 - Submitted Abstract # 326
This version created on 05 October 2006

Sub-Stellar Twins:  Binarity in the Brown Dwarf Regime


Ray Jayawardhana, University of Toronto
Herve Bouy, University of California at Berkeley

Over the past decade, large numbers of very low mass stars and brown
dwarfs have been identified in the solar neighborhood, young clusters
and star-forming regions.  For a variety of reasons, investigating the
frequency and nature of binaries and multiple systems among them is
one of the most exciting areas of cool star research today.  For one,
binary properties of brown dwarfs could be an important diagnostic of
sub-stellar origins.  For another, binaries constitute excellent
laboratories for testing evolutionary models of very low mass objects.
This splinter session will bring together researchers to discuss the
latest findings and prospects for the near future.  There have been a
number of dramatic advances in our understanding of brown dwarf
binarity within the past couple of years.  For example, a planetary
mass companion has been detected next to a nearby young brown dwarf,
and confirmed through common proper motion and infrared spectroscopy.
The first eclipsing brown dwarf binary system was announced within the
past year.  High angular resolution imaging surveys, using adaptive
optics on 8-meter-class telescopes and the Hubble Space Telescope, are
deriving the binary frequency, mass ratios and separations with
sizeable samples of field and young objects;  Astrometric follow up of
several resolved systems is underway to derive dynamical masses.
Radial velocity searches are starting to provide constraints on tight
binary systems.  The current pace of discovery is truly remarkable,
and the session could serve as an opportunity to take stock as well as
to spur on novel ideas and new collaborations.  Many of the leading
players in recent and on-going research efforts have indicated their
intention to attend.  The advent of new instrumental capabilities
(such as LGS AO at Keck and VLT, CRIRES at VLT) is another reason why
this session is timely.

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