New Light on Young Stars:
Spitzer's View of Circumstellar Disks

Characterizing Dusty Disks Around Solar-Like Stars in Sco-Cen

First Author:
Christine Chen
Email: cchen AT stsci.edu
Space Telescope Science Institute
3700 San Martin Drive
Baltimore, MD 21218 USA

Abstract

We have obtained Spitzer Space Telescope IRS observations of 18 solar-like stars with MIPS 24 and 70 micron excesses in the Scorpius-Centaurus OB association with estimated ages of 3 - 20 Myr; and MIPS SED mode observations for a subset of 11 stars. IRAC and MIPS photometric surveys of 10-15 Myr old associations indicate that the dusty disks in Sco-Cen may be experiencing the onset of the debris phase. While the silicate emission bands possess diverse strengths indicating the presence of grains with a variety of sizes and crystalization fractions, the dust in the majority of systems is cold and/or large similar to that found in debris disks. We reproduce the 5-90 micron SEDs assuming thermal emission from olivine, forsterite, and water ice grains located in a ring with a surface density distribution Sigma proportional to r$^{-1.5}$, similar to that inferred from scattered light observations of debris disks.