LEBOUTEILLER V., SLOAN G.C., GROENEWEGEN M.A.T., MATSUURA M., RIEBEL D., WHELAN D.G., BERNARD-SALAS J., MASSEY P. and BAYET E.
Abstract (from CDS):
We report the detection of oxygen-rich circumstellar envelopes in stars of the nearby (700kpc) starburst galaxy IC10. The star-formation history and the chemical environment of this galaxy make it an ideal target to observe dust production by massive stars in a metal-poor environment. The goal of this study is to identify oxygen-rich stars in IC10 and to constrain their nature between asymptotic giant branch stars (AGBs), red supergiants (RSGs), and other bright infrared sources. We examine the mass-loss rates of the stars and compare to results obtained for the Magellanic Clouds. Our objectives are to (1) assess whether RSGs can be significant dust producers in IC10, and (2), solve the discrepancy between the star-formation history of IC10 and the relatively low number of RSGs detected in the optical. We search for silicate dust in emission by using the spectral map observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The optical (UBVRI) and infrared (JHK, Spitzer/IRAC and Spitzer/MIPS) photometry are used to assert the membership of the stars to IC10 and distinguish between AGBs and RSGs. Radiative models are used to infer mass-loss rates and stellar luminosities. The luminosity and colors of at least 9 silicate emission sources are consistent with stars within IC10. Furthermore, the photometry of 2 of these sources is consistent with RSGs. We derive dust mass-loss rates similar to the values found in the Magellanic Clouds. Accounting for the sample completeness, RSGs are not important contributors to the dust mass budget in IC10.