Cool Stars 14 - Submitted Abstract # 41
This version created on 05 October 2006

Subsolar Metallicity Substellar Objects


Adam Burgasser, Massachusetts Institute of Technology

Over the past few years, astronomers have uncovered a handful of
low-temperature, metal-poor objects with halo or thick disk kinematics
and peculiar spectral and photometric properties.  These include the
first examples of L subdwarfs - metal-poor analogs of the L dwarf
spectral class - and a few slightly metal-poor T dwarfs.  Metal
deficient brown dwarfs provide useful empirical tests for brown dwarf
atmospheric and evolutionary models, and are probes of the halo mass
function down to and below the (metal-dependent) hydrogen burning
limit.  In this contributed talk, I will review the optical and
near-infrared signatures of subsolar metallicity in L and T dwarfs,
discuss how these signatures relate to differences in the structure
and chemistry of their atmospheres, and provide suggestions on how to
classify these objects.  I will conclude by describing methods of
optimizing searches for metal-poor L and T dwarfs, with the ultimate
goal of measuring the halo mass function into the substellar regime.

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