Discovery of Extreme Carbon Stars in the Large Magellanic Cloud

Abstract

Using Spitzer IRAC and MIPS observations of the Large Magellanic Cloud, we have identified 13 objects that have extremely red mid-IR colors. Follow-up Spitzer IRS observations of seven of these sources reveal varying amounts of SiC and C2H2 absorption as well as the presence of a broad MgS feature in at least two cases, indicating that these are extreme carbon stars. Preliminary estimates find these objects have luminosities of 4-11x10^3 Lsol and preliminary model fitting gives mass-loss rates between 4x10^-5 and 2x10^-4 Msol/yr, higher than any known carbon-rich AGB star in the LMC. These spectral and physical properties require careful reconsideration of dust condensation and mass-loss processes for carbon stars in low metallicity environments.

Accepted for publication in ApJ Letters. 4 pages, 3 figures

References in corpus (4)

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• Spitzer spectroscopy of carbon stars in the Small Magellanic Cloud
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• An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), I. Overview
• The mass-loss, expansion velocities and dust production rates of carbon stars in the Magellanic Clouds
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• Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud
• A Spitzer/IRAC Characterization of Galactic AGB and RSG Stars
• A WISE view on extreme AGB stars
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• 30-micron sources in galaxies with different metallicities