Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud

A. Z. Bonanos (1), D. J. Lennon (2,3), F. Köhlinger (4), J. Th. van Loon (5), D. L. Massa (2), M. Sewilo (2), C. J. Evans (6), N. Panagia (2,7,8), B. L. Babler (9), M. Block (10), S. Bracker (9), C. W. Engelbracht (9), K. D. Gordon (2), J. L. Hora (11), R. Indebetouw (12), M. R. Meade (9), M. Meixner (2), K. A. Misselt (10), T. P. Robitaille (11), B. Shiao (2) and B. A. Whitney (13)

1 Institute of Astronomy & Astrophysics, National Observatory of Athens, I. Metaxa & Vas. Pavlou St., P. Penteli, 15236 Athens, Greece
2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
3 European Space Agency, Research and Scientific Support Department, Baltimore, MD 21218, USA
4 Department of Physics and Astronomy, Heidelberg University, Albert-Ueberle-Str. 3-5, D-69120 Heidelberg, Germany
5 Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG, UK
6 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK
7 INAF/Osservatorio Astrofisico di Catania, Via Santa Sofia 78, I-95123 Catania, Italy
8 Supernova Ltd., OYV 131, Northsound Road, Virgin Gorda, British Virgin Islands
9 Department of Astronomy, 475 North Charter Street, University of Wisconsin, Madison, WI 53706, USA
10 Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
11 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 67, Cambridge, MA 02138, USA
12 Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903, USA
13 Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA

We present a catalog of 5324 massive stars in the Small Magellanic Cloud (SMC), with accurate spectral types compiled from the literature, and a photometric catalog for a subset of 3654 of these stars, with the goal of exploring their infrared properties. The photometric catalog consists of stars with infrared counterparts in the Spitzer, SAGE-SMC survey database, for which we present uniform photometry from 0.3-24 um in the UBVIJHKs+IRAC+MIPS24 bands. We compare the color magnitude diagrams and color-color diagrams to those of the Large Magellanic Cloud (LMC), finding that the brightest infrared sources in the SMC are also the red supergiants, supergiant B[e] (sgB[e]) stars, luminous blue variables, and Wolf-Rayet stars, with the latter exhibiting less infrared excess, the red supergiants being less dusty and the sgB[e] stars being on average less luminous. Among the objects detected at 24 um are a few very luminous hypergiants, 4 B-type stars with peculiar, flat spectral energy distributions, and all 3 known luminous blue variables. We detect a distinct Be star sequence, displaced to the red, and suggest a novel method of confirming Be star candidates photometrically. We find a higher fraction of Oe and Be stars among O and early-B stars in the SMC, respectively, when compared to the LMC, and that the SMC Be stars occur at higher luminosities. We estimate mass-loss rates for the red supergiants, confirming the correlation with luminosity even at the metallicity of the SMC. Finally, we confirm the new class of stars displaying composite A & F type spectra, the sgB[e] nature of 2dFS1804 and find the F0 supergiant 2dFS3528 to be a candidate luminous blue variable with cold dust.

Reference: Astron.J.140:416-429,2010
Status: Manuscript has been accepted

Weblink: http://adsabs.harvard.edu/abs/2010AJ....140..416B


Email: bonanos@astro.noa.gr