An empirical formula for the mass-loss rates of dust-enshrouded red supergiants and oxygen-rich Asymptotic Giant Branch stars - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2005

An empirical formula for the mass-loss rates of dust-enshrouded red supergiants and oxygen-rich Asymptotic Giant Branch stars

J. Th. van Loon
  • Fonction : Auteur
M. -R. L. Cioni
  • Fonction : Auteur
A. A. Zijlstra
  • Fonction : Auteur

Résumé

We present an empirical determination of the mass-loss rate as a function of stellar luminosity and effective temperature, for oxygen-rich dust-enshrouded Asymptotic Giant Branch stars and red supergiants. To this aim we obtained optical spectra of a sample of dust-enshrouded red giants in the Large Magellanic Cloud, which we complemented with spectroscopic and infrared photometric data from the literature. Two of these turned out to be hot emission-line stars, of which one is a definite B[e] star. The mass-loss rates were measured through modelling of the spectral energy distributions. We thus obtain the mass-loss rate formula log dot{M} = -5.65 + 1.05 log ( L / 10 000 {L}_⊙ ) -6.3 log ( T_eff / 3500 K ), valid for dust-enshrouded red supergiants and oxygen-rich AGB stars. Despite the low metallicity of the LMC, both AGB stars and red supergiants are found at late spectral types. A comparison with galactic AGB stars and red supergiants shows excellent agreement between the mass-loss rate as predicted by our formula and that derived from the 60 μm flux density for dust-enshrouded objects, but not for optically bright objects. We discuss the possible implications of this for the mass-loss mechanism.
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Dates et versions

hal-04111410 , version 1 (07-06-2023)

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Citer

J. Th. van Loon, M. -R. L. Cioni, A. A. Zijlstra, C. Loup. An empirical formula for the mass-loss rates of dust-enshrouded red supergiants and oxygen-rich Asymptotic Giant Branch stars. Astronomy and Astrophysics - A&A, 2005, 438, pp.273-289. ⟨10.1051/0004-6361:20042555⟩. ⟨hal-04111410⟩
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