Spitzer Space Telescope - General Observer Proposal #50440


Thermal Emission from the Super-Earth Orbiting GJ 876

Principal Investigator: Drake Deming
           Institution: NASA's Godddard Space Flight Center

     Technical Contact: Drake Deming, NASA's Godddard Space Flight Center

Co-Investigators: 
Sara Seager, MIT                                                      

Science Category: extrasolar planets 
 Observing Modes: IracMap 
  Hours Approved: 32.9 

Abstract:
GJ 876d is a 7.5 Earth mass non-transiting super-Earth orbiting at 0.025 AU from
its M4V host star. This system is a very near neighbor of the Sun, at only 5 pc
distant, so the thermal flux from the planet will be maximized. We propose to
detect the orbital phase variation of 8 micron thermal emission from the
super-Earth mass planet GJ 876d during ~ 70% of the planet's 1.97 day period
orbit. Our observations will rely on high precision photometry at 8 microns,
focusing exclusively on this crucial capability that will disappear with the
depletion of Spitzer's cryogen. We will detect this planet if it is a bare rock,
or has only a thin atmosphere, for all plausible sizes and albedos. We will use
a novel technical strategy that will "pre-flash" the IRAC detector to eliminate
the time dependence of detector response.