Mid-Infrared Spectral Variability of Actively Accreting T Tauri Stars
First Author:
Jarron Leisenring
Email: jml2u AT virginia.edu
University of Virinia
530 McCormick Road, Astronomy Building, Room 204
Charlottesville, VA 22904
Coauthors:
Bary, Jeff, University of Colgate
Skrutskie, Mike, University of Virginia
Abstract
We present Spitzer IRS data from a multi-epoch mid-infrared spectroscopic survey of 11 actively accreting T Tauri stars in Taurus-Auriga to investigate temporal variations of the gas and dust features residing between 5 and 14 microns. Some objects exhibit the [Ne II] fine structure emission at 12.81 microns as well as the H I (7-6) emission line at 12.37 microns, both of which exhibit marginally detected variability in line flux. A correlation between these gas phase features would suggests a common origin for their emission and have the potential to constrain the responsible mechanisms. In addition, we detect a water vapor absorption band centered between 5.6 and 5.8 microns in the majority of our objects that varies on the timescale of months. We also report on the detection of variability in the 10 micron silicate feature in a few of our objects. The high accretion rates previously measured for the sources in our survey suggest that the variations in these gas phase features as well as those of the silicate features may be due to fluctuations in the accretion luminosity, high energy photons incident upon the disk, and possible line-of-sight effects due to mixing in and rotation of the disks.
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