Spitzer Space Telescope - General Observer Proposal #40389


IRAC reflectances of KBOs, Centaurs, and Trojan asteroids

Principal Investigator: Joshua Emery
           Institution: SETI Institute / NASA Ames

     Technical Contact: Joshua Emery, SETI Institute / NASA Ames

Co-Investigators: 
Dale Cruikshank, NASA Ames                                            
Cristina Dalle Ore, SETI Institute/NASA Ames                          
Yanga Fernandez, University of Central Florida                        
John Stansberry, University of Arizona                                
David Trilling, University of Arizona                                 
Janusz Eluszkiewicz, Atmospheric and Environmental Research, Inc.     

Science Category: Kuiper belt objects 
 Observing Modes: IracMap 
  Hours Approved: 87.1 

Abstract:
We propose to measure broadband fluxes of Kuiper Belt Objects (KBOs), Centaurs,
and Trojan asteroids with IRAC in order to determine surface compositions. The
value of IRAC is that its measurements of reflectance will 1) provide a far more
sensitive search for ices than is possible at shorter wavelengths and 2) readily
distinguish between candidates for the poorly understood "dark material," which
is also not possible at shorter wavelengths. These capabilities critically
address several longstanding questions in planetary science: What is the nature
of the dark material that is nearly ubiquitous in the outer Solar System? Is it
a single material or does its composition vary on different bodies in or from
different locations? and What is the distribution of volatiles? For several
objects, thermal emission will be detected in the 8.0-micron band. The
simultaneous measurement with IRAC of both reflected and emitted flux will
permit estimation of size and albedo for these objects. Our cycle-2 program to
observe an initial set of outer Solar System objects has been tremendously
successful, and this proposal builds on that success.