Spitzer Space Telescope - General Observer Proposal #20438


Mass Loss From Stars in Globular Clusters

Principal Investigator: Joel Bregman
           Institution: Univerisity of Michigan

Co-Investigators: 
Mario Mateo, University of Michigan                                   
Patrick Seitzer, University of Michigan                               

Science Category: star clusters 
 Observing Modes: IrsMap 
  Hours Approved: 9.7 

Abstract:
Evolved stars reveal the presence of mass-loss through their excess
10um emission, which comes from silicate grains that are heated in
slow stellar winds.  This has been a lively research area for nearby
field giants, but with Spitzer, mass loss finally can be studied in
globular clusters, systems with well-defined ages and metallicities.
We propose to measure the strength of the silicate emission as a
function of metallicity and age for selected globular clusters in the
Milky Way and the LMC.  These measurements will yield the cluster-wide
stellar mass loss rates, a critical test of stellar evolutionary
models.  Of equal importance, these observations will enable us to
age-date early-type galaxies, breaking the age-metallicity degeneracy
that plagues the other main method.