Cool Stars 14 - Submitted Abstract # 138
This version created on 05 October 2006

Atmospheric properties of L dwarfs evidenced by spectral features in
the infrared (5-15 micron)


Mollie Van Gordon, Barnard, AMNH
Kelle Cruz, AMNH

We present Spitzer IRS low-resolution spectra of L dwarfs (5-15
microns).  Our infrared spectra confirm the silicate feature in the 9
to 11 micron range of early-to-mid L dwarfs proposed by Cushing et al.
2006 that likely indicates the presence of small-grained silicate
clouds composed of enstatite as well as forsterite not included in the
current atmospheric models for brown dwarfs.  Our spectra demonstrate
the variability of the presence of the silicate feature as well as the
variable strength of water features in L dwarfs.  The spectra will
eventually be compared with theoretical models, offering insight into
the role of gravity, metallicity, and cloud properties of the
atmospheres of brown dwarfs in their resultant spectra.

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