Cool Stars 14 - Submitted Abstract # 244
This version created on 05 October 2006

The first field brown dwarf discovered by Spitzer


Peter Eisenhardt, JPL
Daniel Stern, JPL
J. Davy Kirkpatrick, IPAC
Ned Wright, UCLA
Lori Allen, CfA
Chao Bian, Caltech
Andrew Blain, Caltech
Kate Brand, STScI
Mark Brodwin, JPL
Michael Brown, Princeton University
Richard Cool, U. of Arizona
Vandana Desai, Caltech
Arjun Dey, NOAO
Anthony Gonzalez, U. of Florida
Buell Jannuzi, NOAO
Karin Menendez-Delmestre, Caltech
Howard Smith, CfA
B.T. Soifer, Caltech
Glenn Tiede, Bowling Green State University

We present the first field brown dwarf discovered by Spitzer.  ISS
J142950.9+333012 was identified in the 8 square degree IRAC Shallow
Survey of the Bootes field of the NOAO Deep Wide-Field Survey, using a
selection for objects with Vega-system colors [3.6] - [4.5] > 0.4, R -
I > 2.5, and which were unresolved in the I-band.  Followup optical
spectroscopy with the MARS spectrograph on the Mayall 4m telescope at
Kitt Peak, and infrared spectroscopy with NIRSPEC on Keck II, show ISS
J142950.9+333012 is a T4.5 brown dwarf at a distance of approximately
42 pc.  The selection criteria also identified quasars at redshifts of
5.5, 5.9, and 6.1, the latter being one of only 10  known above
redshift 6.  The criteria restrict the possible brown dwarf spectral
type range to approximately T3 through T6.  We discuss the
implications of this discovery for the field brown dwarf population,
and for searches for cooler brown dwarfs with the Wide-field Infrared
Survey Explorer (WISE), planned for launch in 2009.

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