Cool Stars 14 - Submitted Abstract # 275
This version created on 05 October 2006

Precision Masses of Very-Low-Mass Stars and Brown Dwarfs with
Aperture-Masking Interferometry and Astrometry


Michael Ireland, Caltech
Frantz Martinache, Cornell
James Lloyd, Cornell 
Ryan Yamada, Cornell
Steve Pravdo, JPL
Stuart Shaklan, JPL
Peter Tuthill, University of Sydney

We present the latest results from our program of high-contrast
optical-interferometry at the diffraction limit of the Palomar and
Keck telscopes.  This technique is capable of making clear detections
of binaries with 100:1 contrast ratio at the formal diffraction limit
of \lambda/D.  We have combined our measurements with
sub-milli-arcsecond astrometry from the STEPS program and published
radial velocities to provide accurate dynamical mass estimates for 7
dwarfs.  The secondary masses range from 0.06 to 0.19 solar masses,
with accuracies ranging from approximately 1 to 10%.  We also discuss
the likely possibility of these techniques providing a dymical mass
estimate for a directly detected planetary mass candidate in the near
future.

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