Cool Stars 14 - Submitted Abstract # 72
This version created on 05 October 2006

Characterizing the disk around the brown dwarf planetary system 2MASSW
J1207334-393254


Basmah Riaz, University of Delaware
John E. Gizis, University of Delaware

The brown dwarf planetary system 2MASSW J1207334-393254 consists of a
30  MJUP primary and a 5 MJUP extrasolar planet.  The primary is known
to be undergoing active accretion, and harbors a circumsubstellar disk
of gas and dust, detected by excess emission in the IR.  Previous
measurements of IR excess emission were too few in number to correctly
model the disk spectral energy distribution.  Existing results suggest
a high inclination angle (> 60º) with an inner hole that can be fit by
both a large grain size, large inclination angle flared disk and a
small grain size flat disk.  Using our SPITZER observations from 3.6
to 24 micron, we are trying to fit disk models described in Walker et
al.  (2003) and determine important disk parameters.  We believe our
24 micron data point is valuable in determining the surface geometry
of the disk, as it probes more distant regions (~1AU) from the central
object.  An estimate of the outer disk radius will be important to
show if the planetary companion has any effect on disk emission.  We
have extended our work to another TWA BD, 2MASSW J1139511-315921, that
shows evidence of inner disk clearing, as no excess emission was
detected shortward of 24 micron.  The excess at 24 micron, however, is
inadequate to determine the disk geometry, and our model fit suggests
that for such a 'transition disk', measurements at longer wavelengths
are required to find out if the disk flares up at larger radii from
the central object.

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