FM16.3.03 — CO thermal emissions and mass loss of red-supergiants beyond the Milky Way

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Aug 4th at 11:15 AM until 11:30 AM

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Author(s): Mikako Matsuura1, Benjamin Sargent6, J. Yates8, B. Swinyard8, P. Royer2, M Boyer4, M.J. Barlow8, Margaret Meixner7, Leen Katrien Els Decin2, T. Khouri2, J. van Loon3, P. Woods5

Institution(s): 1. Cardiff University, 2. Katholieke Universiteit Leuven, 3. Keele University, 4. NASA God- dard Space Flight Center, 5. Queen’s University Belfast, 6. Rochester Institute of Technology, 7. Space Telescope Science Institute, 8. University College London

It is crucial for understanding stellar evolution to study how red-supergiants lose their mass. Although mass loss of red-supergiants has been well studied in the Milky Way, it is poorly studied beyond the Milky Way. Particularly, galaxies have wide range of metallicities, and the key question is how metallicity affects dust formation in red-supergiants, hence, how dust-driven mass-loss could be affected by the metallicity. Theory predicted that mass loss rate is lower at low metallicity. Testing this hypothesis, we observed CO thermal emission lines in red-supergiants in the Large Magellanic Cloud, using the Herschel Space Observatory. These are the first detections of rotational CO lines from red-supergiants beyond the Milky Way. Although the metallicity of the Large Magellanic Cloud is about the half of the solar metallicity, no obvious metallicity effect was found on the gas mass-loss rate. The key parameter for the mass-loss rate is the luminosity of the star.