Spitzer Space Telescope - General Observer Proposal #40238


A search for Mars-mass extrasolar planets with Spitzer

Principal Investigator: Eric Agol
           Institution: University of Washington

     Technical Contact: Eric Agol, University of Washington

Co-Investigators: 
David Charbonneau, Harvard University                                 
Drake Deming, Goddard Space Flight Center                             
Jason Steffen, Fermilab                                               
Heather Knutson, Harvard University                                   
Nicolas Cowan, University of Washington                               

Science Category: extrasolar planets 
 Observing Modes: IracMap 
  Hours Approved: 63.6 

Abstract:
We propose to make 6 observations of the transits of the hot Jupiter planet HD
189733b and six observations of its secondary eclipse in order to detect
variations of the times of transit/eclipse due to secondary planets in the
system, if present. Spitzer is the best telescope for transit timing of this
system, allowing nearly an order of magnitude better timing precision than HST
or ground-based observations (for any transiting planet), as already
demonstrated with prior Spitzer observations of this target. These observations
will be sensitive to the presence of Mars-mass bodies in mean-motion resonance
with the transiting planet. We will utilize the IRAC 8 micron camera as this has
the best trade-off in stability and source brightness to allow for the highest
timing precision. In addition we will constrain the eccentricity of the
transiting planet and we will search for variations in the depth of the
secondary eclipse which are predicted by models of weather on hot Jupiter
planets.