Spitzer Space Telescope - General Observer Proposal #60063


Exoplanet HAT-P-11b Secondary Transit Observations

Principal Investigator: Richard Barry
           Institution: NASA Goddard Space Flight Center

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

Co-Investigators: 
Gaspar Bakos, Harvard-CfA                                             
L. Drake Deming, NASA Goddard                                         
Joseph Harrington, University of Central Florida                      
Nikku Madhusudhan, MIT                                                
Robert Noyes, Harvard-CfA                                             
Sarah Seager, Massachusetts Institute of Technology                   

Science Category: extrasolar planets 
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 48.2 

Abstract:
We propose to conduct secondary eclipse observations of exoplanet HAT-P-11b,
recently discovered by proposal Co-Investigator G. Bakos and his colleagues.
HAT-P-11b is the smallest transiting extrasolar planet yet found and one of only
two known exo-Neptunes. We will observe the system at 3.6 microns for a period
of 22 hours centered on the anticipated secondary eclipse time, to detect the
eclipse and determine its phase. Once the secondary eclipse is located, we will
make a more focused series of observations in both the 3.6 and 4.5 micron bands
to fully characterize it. HAT-P-11b has a period of 4.8878 days, radius of 0.422
RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary
eclipse will clarify two key issues; 1) the planetary brightness temperature and
the nature of its atmosphere, and 2) the eccentricity of its orbit, with
implications for its dynamical evolution. A precise determination of the orbit
phase for the secondary eclipse will also be of great utility for Kepler
observations of this system at visible wavelengths.