Year: 2007
Type: article
Abstract: We analyze five epochs of Spitzer Space Telescope Infrared Array Camera (IRAC) observations of the nearby spiral galaxy M33. Each epoch covered nearly a square degree at 3.6, 4.5, and 8.0 μm. The point-source catalog from the full data set contains 37,650 stars. The stars have luminosities characteristic of the asymptotic giant branch and can be separated into oxygen-rich and carbon-rich populations by their [3.6] - [4.5] colors. The [3.6] - [8.0] colors indicate that over 80% of the stars detected at 8.0 μm have dust shells. Photometric comparison of epochs using conservative criteria yields a catalog of 2923 variable stars. These variables are most likely long-period variables amid an evolved stellar population. At least one-third of the identified carbon stars are variable.
Source: The Astrophysical Journal
DOI: 10.1086/519068
Authors: K. B. W. McQuinn, Charles E. Woodward, S. P. Willner, E. F. Polomski, R. D. Gehrz, Roberta M. Humphreys, Jacco Th. van Loon, M. L. N. Ashby, K. Eicher, G. G. Fazio
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2049916254