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9 March 2009
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Quinn Konopacky (UCLA)
"High Precision Dynamical Masses for Brown Dwarfs"
I will present new dynamical mass estimates for a sample of brown dwarf
binaries with sufficient precision (< 10%) to distinguish between current
theoretical evolutionary models. This survey has used both NIRC2 and NIRSPEC
on Keck II with the laser guide star adaptive optics (LGS AO) system to
target 20 sources between spectral types M8 and T5.5. The LGS AO system
combined with these instruments allows both high precision (dpos < 1 mas)
astrometry and spatially resolved, high-resolution spectroscopy (drv < 1
km/s). I will discuss preliminary results from this survey, which show that
there are systematic offsets between the dynamical masses and the predicted
masses from models as a function of spectral type. The fact that there is a
trend with spectral type suggests a discrepancy in temperature estimates,
which in turn depend on the assumed atmospheric physics for these objects. I
will conclude by discussing future measurements of individual masses of the
components each binary system and how these results will impact comparisons
with the models.
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