Program: GS-2006A-DD-5

We propose near-infrared spectroscopy and photometry of the white dwarf SDSS J121209.31+013627.7 in order to directly detect light from the probable brown dwarf companion in this short period binary system. The secondary may be the first T dwarf -- both the coolest (~ 1000 K) and the lowest mass (~ 40 jupiters) -- companion ever discovered around a white dwarf. These observations will constrain mass estimates for the companion, help to determine its effective temperature and spectral type, provide much needed insight into formation and evolution scenarios important for understanding substellar companion evolution during the post main sequence phases and, if the brown dwarf has survived Common Envelope evolution, provide important constraints on models for close binary formation and envelope ejection.