Spitzer Space Telescope - Directors Discretionary Time Proposal #80263

3.6um and 4.5um Secondary Eclipse Observations of the Highly Irradiated 
Transiting Brown Dwarf KELT-1b


Principal Investigator: Thomas Beatty
           Institution: Ohio State University

     Technical Contact: Thomas Beatty, Ohio State

Co-Investigators:
Scott Gaudi, Ohio State University
Jason Eastman, LCOGT and UC Santa Barbara
Jonathan Fortney, UC Santa Cruz
Heather Knutson, Caltech
Joshua Pepper, Vanderbilt
Robert Siverd, Vanderbilt
Keivan Stassun, Vanderbilt 

Science Category: extrasolar planets
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 13.5

Abstract:
The transiting brown dwarf KELT-1b provides us with a unique opportunity to 
how brown dwarfs and exoplanets relate to one another, or if they are even 
distinct. It is a 27 Jupiter-mass object on a short 1.2 day orbit around a 
bright (V=10.8) F5V star. KELT-1b allows us to study a brown dwarf where 
we know the mass, radius and age -- in an environment similar to hot Jupiters 
and around a star bright enough to allow for precision follow-up observations. 
KELT-1b is also specifically interesting because it is substantially inflated 
as compared to models for brown dwarfs at the age of the KELT-1 system. This 
is the first instance of an inflated brown dwarf, and whether the inflation 
mechanism is related to that of hot Jupiters or low-mass stars is unclear. 
We therefore are proposing to observe two secondary eclipses: one at 3.6 um 
and one at 4.5 um. The information provided by the secondary eclipses will 
allow us to begin to characterize the atmospheric composition, dynamics, and 
structure of KELT-1b in such a way that we may begin to relate the observed 
properties of field brown dwarfs to those of hot Jupiters, and to discover 
how it has been inflated. Our proposed observations will also allow us to 
gauge the feasibility of a Spitzer GO proposal to observe orbital phase variation 
in the light from KELT-1, to be submitted this fall.