Spitzer Space Telescope - Directors Discretionary Time Proposal #50780


Completing the Dust Census of the Saturn System

Principal Investigator: Anne Verbiscer
           Institution: University of Virginia

     Technical Contact: Anne Verbiscer, University of Virginia

Co-Investigators: 
Michael Skrutskie, Univ. of Virginia                                  
Douglas Hamilton, Univ. of Maryland                                   

Science Category: satellites 
 Observing Modes: MipsScan 
  Hours Approved: 2.5 

Abstract:
We request a modest amount of time to conduct a speculative program to search
for extended dust structures in the saturnian system with an origin associated
with Iapetus. Under the influence of Poynting-Robertson drag and dynamical
interaction, particles originating from this moon will uniformly populate a
large toroidal region around Saturn. Recent images obtained by the Cassini
spacecraft indicate that Iapetus, like Enceladus, may endogenically modify its
surface and can thus be a source of such particles through intrinsic "cometary"
and/or cryovolcanic activity. This proposal follows up on Spitzer Program 40840
to search for such a dust structure associated with the satellite Phoebe. We
will explore the likelihood that recent activity on Iapetus could produce dust
structure surrounding Saturn that is detectable by Spitzer with contrast above
the zodiacal background in less than 3 hours of observation.