Spitzer Space Telescope - Directors Discretionary Time Proposal #544


The Peculiar Object P/2010 A2 (LINEAR)

Principal Investigator: Michael Kelley
           Institution: University of Maryland

     Technical Contact: Michael Kelley

Co-Investigators: 
William Reach, IPAC
David Trilling, NAU
Jeremie Vaubaillon, IMCCE/Paris
Michael Mueller, Obs. Cote dAzure
Josh Emery, Univ. Tennessee Knoxville

Science Category: asteroids
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 8.3

Abstract:
We propose an 8.3 hr low-impact Target of Opportunity DDT proposal to assess 
the nature of the newly discovered comet P/2010 A2 (LINEAR) and the associated 
asteroid 2010 AA15 with Spitzer/IRAC. The orbital elements of comet A2 and 
asteroid AA15 securely place them in the inner-asteroid belt and close to the 
Flora family of asteroids.  The existence of cometary objects within the 
asteroid belt is a hot topic in planetary science because it blurs the 
distinction between the comets and asteroids and opens the possibility of 
significant volatile content in asteroids.  However, comet A2 may instead be 
the result of a never before seen collision between two asteroids. This 
provides us with a unique opportunity to measure the amount of dust produced 
in sub-km asteroid collisions and to provide "ground-truth" measurements of 
the dust observed in debris disks around main sequence stars. Our proposed 
program will measure the optical depth and color of the dust, allow us to 
search for thermal emission from the asteroid as well as molecular emission 
from CO or CO2 gas.