Spitzer Space Telescope - Guaranteed Time Observer Proposal #40030


Circumstellar Debris Disks Around Nearby, Young M Dwarfs

Principal Investigator: Giovanni Fazio
           Institution: Harvard-Smithsonian Center for Astrophysics

     Technical Contact: Patrick Lowrance, Caltech

Co-Investigators: 
Patrick Lowrance, Caltech/SSC                                         
Massimo Marengo, Center for Astrophysics                              
David Ardila, Caltech/SSC                                             

Science Category: circumstellar/debris disks 
 Observing Modes: IracMap MipsPhot 
  Hours Approved: 17.0 

Abstract:
Planetary systems are currently believed to form within a circumstellar debris
disk. Previous studies have identified over a hundred such debris disks around
A, F, and G-type dwarfs from their thermal IR emission. However, very little is
known about debris disks around M dwarfs, as only two debris disk systems around
M dwarfs have been confirmed. Even though they are the most populous stars in
our solar neighborhood, M dwarfs are often overlooked because of instrumental
sensitivity; these low-mass stars have low luminosities and temperatures. But,
if forming planetary systems exist around these stars, they would be the most
numerous and represent a population worth examining. We propose to use the
extraordinary sensitvity provided by MIPS on Spitzer to search for debris disks
around a sample of nine young (~100Myr), nearby M dwarfs. The exposure times
have been chosen to measure the photosphere from 3-70um. Based on current
estimates of disk fractions, we should discover 1-2 debris disks, which will
almost double the number of disks known around low-mass stars. Since M dwarfs
are most likely the most common host of planetary systems, comparing their
debris disks to those around higher mass stars will shed light on the diversity
of planetary architectures. Divisions: There is 0.6 hour total using IRAC, and
16.4 hrs total using MIPS.