Spitzer Space Telescope - General Observer Proposal #20742


Spitzer imaging and photometry of two 1 Gyr old debris disks within 20
pc of the Sun

Principal Investigator: Mark Clampin
           Institution: NASA GSFC

Co-Investigators: 
Paul Kalas, UC Berkeley                                               
James Graham, UC Berkeley                                             

Science Category: circumstellar/debris disks 
 Observing Modes: IracMap MipsPhot MipsSed 
  Hours Approved: 12.8 

Abstract:
We report the first scattered light detections of two debris disk
around an F star and a K star using optical coronagraphy and the
Hubble Space Telescope.  With ages ~1 Gyr, these are the oldest debris
disks thus far seen in the optical.  We have discovered ring-like
structure and azimuthal asymmetry that can be linked to dynamical
perturbations of yet-undetected planetary companions.  We propose
deep, multi-roll angle IRAC imaging with SST to search for substellar
objects, to constrain the presence of a warm dust component in the
disk, and to identify its spatial location within the disk's
structure.  MIPS photometry will be employed to anchor the spectral
energy distribution of the disks at longer wavelengths.  Since these
debris disks are close to our Kuiper Belt in an evolutionary context,
detailed understanding of their mass, structure and composition will
provide a fresh perspective for inferring the history and properties
of our own trans-Neptunian region.