Groenewegen, M. ; Sloan, G. C.

published in Proceedings of The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments (LCDU2013). 18-22 November, 2013. Taipei, Taiwan. Editors: Anja Andersen (University of Copenhagen, Denmark), Maarten Baes (Universiteit Gent, Belgium), Haley Gomez (Cardiff University, UK), Ciska Kemper (Academia Sinica, Taiwan), Darach Watson (University of Copenhagen, Denmark). Online at http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=207, id.94, pp. 94 (2013)

Abstract: Dusty radiative transfer models are presented for 210 carbon stars and 166 oxygen-rich evolved stars in the Magellanic Clouds and other nearby dwarf galaxies for which Spitzer IRS spectra are available. The spectra are complemented with available optical and infrared photometry to construct spectral energy distributions. A dust radiative transfer code and a minimisation procedure are used to determine the best-fitting luminosity and mass-loss rate. This presentation focuses on the mass-loss rates determined for the carbon stars. The potentially most interesting result is that a significant number of stars, about 5% of the sam˙ exp )/(L/c) (the ratio of the matterple, has a mass-loss rate that translates to a value of β ≡ (Mv momentum flux to the photon-momentum flux) which is larger than the single-scattering limit and up to a value of ˜10. If confirmed, this result would impact stellar evolution models which sometimes limit the mass-loss rate to β = 1. A full paper will follow with a more complete presentation for the larger sample.

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