V. Lebouteiller (CEA-Saclay), G.C. Sloan (Cornell), M.A.T. Groenewegen (Royal Obs. Belgium), M. Matsuura (Univ. Coll. London), D. Riebel (Johns Hopkins and Naval Academy), D.G. Whelan (Univ. of Virginia), J. Bernard-Salas (Inst. d'Astrophys. Spatiale), P. Massey (Lowell Obs.), E. Bayet (Univ. of Oxford).
2012, A&A, 546, 94
Full manuscript available locally (PDF) or from the arXiv (1209.1023).
Context: We report the detection of oxygen-rich circumstellar envelopes in
stars of the nearby (700 kpc) starburst galaxy IC 10. 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.
Aims: The goal of this study is to identify oxygen-rich stars in IC 10
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 IC 10, and (2), solve the
discrepancy between the star-formation history of IC 10 and the
relatively low number of RSGs detected in the optical.
Methods: 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 IC 10 and distinguish between AGBs and RSGs. Radiative
models are used to infer mass-loss rates and stellar luminosities.
Results: The luminosity and colors of at least 9 silicate emission
sources are consistent with stars within IC 10. 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 IC 10.
Last modified 15 October, 2012. © Gregory C. Sloan and others.