SURVEYING THE AGENTS OF GALAXY EVOLUTION IN THE TIDALLY STRIPPED, LOW METALLICITY SMALL MAGELLANIC CLOUD (SAGE-SMC). II. COOL EVOLVED STARS

Journal Article · Sat Oct 15 00:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/142/4/103· OSTI ID:21582852

Boyer, Martha L; Meixner, Margaret; Gordon, Karl D; Shiao, Bernie ^[1]; Srinivasan, Sundar ^[2]; Van Loon, Jacco Th ^[3]; McDonald, Iain; Kemper, F ^[4]; Zaritsky, Dennis; Block, Miwa; Engelbracht, Charles W; Misselt, Karl ^[5]; Babler, Brian; Bracker, Steve; Meade, Marilyn; Whitney, Barbara ^[6]; Hora, Joe; Robitaille, Thomas ^[7]; Indebetouw, Remy ^[8]; Sewilo, Marta ^[9]

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1. STScI, Baltimore, MD 21218 (United States)
2. Institut d'Astrophysique de Paris, CNRS UPR 341, Paris F-75014 (France)
3. Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom)
4. Jodrell Bank Centre for Astrophysics, University of Manchester, M13 9PL (United Kingdom)
5. Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
6. Department of Astronomy, University of Wisconsin, Madison, Madison, WI 53706-1582 (United States)
7. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138-1516 (United States)
8. Department of Astronomy, University of Virginia, Charlottesville, VA 22903-0818 (United States)
9. Department of Physics and Astronomy, The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States)

We investigate the infrared (IR) properties of cool, evolved stars in the Small Magellanic Cloud (SMC), including the red giant branch (RGB) stars and the dust-producing red supergiant (RSG) and asymptotic giant branch (AGB) stars using observations from the Spitzer Space Telescope Legacy program entitled 'Surveying the Agents of Galaxy Evolution in the Tidally Stripped, Low Metallicity SMC', or SAGE-SMC. The survey includes, for the first time, full spatial coverage of the SMC bar, wing, and tail regions at IR wavelengths (3.6-160 {mu}m). We identify evolved stars using a combination of near-IR and mid-IR photometry and point out a new feature in the mid-IR color-magnitude diagram that may be due to particularly dusty O-rich AGB stars. We find that the RSG and AGB stars each contribute {approx}20% of the global SMC flux (extended + point-source) at 3.6 {mu}m, which emphasizes the importance of both stellar types to the integrated flux of distant metal-poor galaxies. The equivalent SAGE survey of the higher-metallicity Large Magellanic Cloud (SAGE-LMC) allows us to explore the influence of metallicity on dust production. We find that the SMC RSG stars are less likely to produce a large amount of dust (as indicated by the [3.6] - [8] color). There is a higher fraction of carbon-rich stars in the SMC, and these stars appear to reach colors as red as their LMC counterparts, indicating that C-rich dust forms efficiently in both galaxies. A preliminary estimate of the dust production in AGB and RSG stars reveals that the extreme C-rich AGB stars dominate the dust input in both galaxies, and that the O-rich stars may play a larger role in the LMC than in the SMC.

• OSTI ID: 21582852
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 142, Issue 4; Other Information: DOI: 10.1088/0004-6256/142/4/103; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CARBON
CARBON STARS
COLOR
DUSTS
GALACTIC EVOLUTION
MAGELLANIC CLOUDS
METALS
PHOTOMETRY
POINT SOURCES
STAR EVOLUTION
SUPERGIANT STARS
TELESCOPES
ELEMENTS
EVOLUTION
GALAXIES
GIANT STARS
MAIN SEQUENCE STARS
NONMETALS
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
RADIATION SOURCES
STARS