Cool Stars 14 - Submitted Abstract # 235
This version created on 05 October 2006

Searching for Metal-Poor L and T Dwarfs:  An Adaptive Optics Survey of
Cool Subdwarf Stars


Christopher Gelino, Spitzer Science Center
J. Davy Kirkpatrick, IPAC

The spectra of L and T dwarfs can be affected by effective
temperature, gravity, and metallicity.  Of these, metallicity effects
are the most poorly understood because so few L and T dwarfs with
known metallicity have been discovered.  Those with suspected low
metallicity are solitary objects in the field, where their exact metal
content is difficult to ascertain.  One way to constrain the effects
of low metal content in an L or T dwarf atmosphere is to find L or T
dwarfs as companions to stars with known metal-poor atmospheres (as
determined by much more mature stellar atmosphere models).  To this
end we have conducted an adaptive optics survey of ~50  cool subdwarf
stars with the Keck telescope to search for very low-mass companions.
We present the preliminary results of this survey and discuss the
binarity fraction of our sample and the prospects of finding
metal-poor L and T dwarf companions.

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