Presentation Abstract

Presentation Number 342.03
Presentation Time: Wednesday, Jan 12, 2011, 9:00 AM - 6:30 PM
Title Spitzer Observations of Stellar Variability in the Mid-Infrared
Author Block Richard DeCoster1, P. Piper2, B. Thomas3, A. Antonow1, A. Sehgal1, R. Rosignolo2, J. Romero2, O. Rudio3, D. Brennan3, D. W. Hoard4, S. Howell5
1Niles West High School, 2Lincoln-Way North High School, 3North Middle School, 4Spitzer Science Center, California Institute of Technology, 5NOAO.
Abstract We used archival mid-infrared data from the Spitzer Space Telescope to search three Infrared Array Camera (IRAC) fields containing exoplanet host stars (Tres-2, Hat-P-1b, and Tres-4) for additional stars that vary in the mid-infrared. We used the Image Reduction and Analysis Facility (IRAF) software to determine photometry for all field stars detected by 2MASS, plus a number of manually selected stars in each field that were not contained in the 2MASS Point Source Catalog. In total, 242 stars in 6447 images were surveyed (62 stars in 1073 4.5-micron images of the Tres-2 field spanning 3.5 hr, 49 stars in 1605 3.6-micron and 4.5-micron images of the Hat-P-1b field spanning 6.0 hr, and 131 stars in 2164 4.5-micron images of the Tres-4 field spanning 8.0 hr). We created light curves for each of the stars and visually inspected these light curves for variability above the level of the noise. We found one star in the Tres-4 field that displayed periodic variability (P = 0.082 days) when phase-folded. We noted that this star was not listed in the 2MASS catalogue. Thus, we found that approximately 0.4% of stars observed in the mid-infrared, down to our sensitivity level (approximately 0.15 mJy at 4.5 microns for a S/N = 5 detection), exhibit variability. This research was conducted within the NASA/IPAC Teacher Archive Research Project (NITARP).