Spitzer Space Telescope - General Observer Proposal #60205

Measuring X-ray Heating of Circumstellar Disks: Linking Stellar 
X-ray Flares With Mid-IR Disk Afterglows

Principal Investigator: Kevin Covey
           Institution: Harvard SAO

     Technical Contact: Kevin Covey, SAO

Co-Investigators:
Jan Forbich, SAO
Scott Wolk, SAO
John Stauffer, SSC
Luisa Rebull, SSC
Maria Morales, LAEFF
Rob Gutermuth, Smith College
Peter Plavchan, IPAC/Caltech
Tom Megeath, Univ. Toledo
Barbara Whitney, Space Science Inst.
Joe Hora, SAO

Science Category: brown dwarfs/very low mass stars
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 7.0

Abstract:
We propose to obtain Chandra ACIS-I observations of two young 
clusters, IC1396A and Ceph C, to test theoretical predictions of 
X-ray heating in circumstellar disks. Leveraging this Chandra data 
with extensive mid-IR light curves from our Spitzer Warm Mission 
program (YSOVAR), we will: 1) test if YSO X-ray and mid-IR 
variability are statistically correlated, indicating that stellar 
X-ray emission heats disks significantly, and 2) test if disk 
accretion rates rise following stellar X-ray flares, as expected 
from disk accretion models driven by magneto-rotational 
instabilities. Ancillary science includes: A) identification of weak 
T Tauri stars, to study their mid-IR variability; B) cluster 
extinction measurements; and C) LX/rotation relations with mid-IR 
periods for embedded protostars.