The mass-loss rates of red supergiants at low metallicity: detection of rotational CO emission from two red supergiants in the Large Magellanic Cloud
Journal article, 2016
Using the PACS and SPIRE spectrometers on-board the Herschel Space Observatory, we obtained spectra of two red supergiants (RSGs) in the Large MagellanicCloud (LMC). Multiple rotational CO emission lines (J = 6-5 to 15-14) and 15 H2O lines were detected from IRAS 05280-6910, and one CO line was detected from WOH G64. This is the first time that CO rotational lines have been detected from evolved stars in the LMC. Their CO line intensities are as strong as those of the Galactic RSG, VY CMa. Modelling the CO lines and the spectral energy distribution results in an estimated mass-loss rate for IRAS 05280-6910 of 3 x 10(-4) M-circle dot yr(-1). The model assumes a gas-to-dust ratio and a CO-to-H-2 abundance ratio is estimated from the Galactic values scaled by the LMC metallicity ([Fe/H] similar to -0.3), i.e. that the CO-to-dust ratio is constant for Galactic and LMC metallicities within the uncertainties of the model. The key factor determining the CO line intensities and the mass-loss rate found to be the stellar luminosity.
stars: mass-loss
circumstellar matter
Magellanic Clouds
ISM: molecules
stars: massive
stars: AGB and post-AGB
Author
M. Matsuura
Cardiff University
UCL
B. Sargent
Rochester Institute of Technology
B. Swinyard
Rutherford Appleton Laboratory
UCL
J. A. Yates
UCL
P. Royer
KU Leuven
M. J. Barlow
UCL
M. Boyer
NASA Goddard Space Flight Center
L. Decin
Astronomical Institute Anton Pannekoek
KU Leuven
Theo Khouri
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
M. Meixner
Johns Hopkins University
STScI
J. T. van Loon
Keele University
P. M. Woods
Queen's University Belfast
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 462 3 2995-3005 stw1853Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
Infrastructure
Onsala Space Observatory
DOI
10.1093/mnras/stw1853