Spitzer Space Telescope - Guaranteed Time Observer Proposal #30252


Precision Thermal Observations of Rotational Variability in Main Belt
Asteroids

Principal Investigator: Giovanni Fazio
           Institution: Harvard-Smithsonian Astrophysical Observatory

Co-Investigators: 
Bidushi Bhattacharya, Caltech/Spitzer Science Center, USA             
Thomas Mueller, Max Planck Institut for Extraterrestrial Physics,     
William Reach, Caltech/Spitzer Science Center, USA                    
Vikki Meadows, Caltech/Spitzer Science Center, USA                    
Mikko Kaasalainen, Dept of Mathematics and Statistics, Univ. of Helsi 

Science Category: asteroids 
 Observing Modes: IracMap 
  Hours Approved: 19.0 

Abstract:
Temporal variability in optical flux from main belt asteroids is tied
strongly to shape and albedo changes as these bodies rotate and also
changes with illumination and observing geometry.  At thermal
wavelengths, surface properties are also responsible for second order
effects on the light curve.  As the variation with time of
mid-infrared flux is not well-characterized, we propose to observe
thermal variations as a function of rotation for a selected set of
main belt asteroids of different taxonomic classes using Spitzer/IRAC
at 8 um.