Spitzer Space Telescope - Directors Discretionary Time Proposal #225


Spitzer Observations of a WZ Sge-Type Dwarf Novae in Superoutburst

Principal Investigator: David Ciardi
           Institution: Michelson Science Center

Science Category: evolved stars/pn/sne 
 Observing Modes: IracMap MipsPhot 
  Hours Approved: 5.0 

Abstract:
On 2004 June 16, a previously unknown star in Hercules went into
outburst (IAUC #8363).  Preliminary optical spectra from 0.37 - 0.75um
and 0.7 - 0.9 um, taken after the outburst was reported, indicate that
the outbursting star is a cataclysmic variable of the WZ Sge dwarf
novae type.  As WZ Sge-type dwarf novae rarely outburst (timescales of
decades), we are proposing to take advantage of this unique
opportunity and observe the outburst with Spitzer - a chance that may
never come again.  The requested IRAC and MIPS observations will be
used to explore the question of whether dust is formed in the ejecta
of the outburst, and thus, explain an observed dip in the optical
light curves of WZ Sge-type dwarf novae which has remained unexplained
for nearly six decades.