M supergiants in the Milky Way and the Magellanic Clouds Colors, spectral types, and luminosities

1985/01/01 by J. H. Elias, J. A. Frogel, R. M. Humphreys · 13 citations
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena

paper · doi:10.1086/190997

Abstract

The differences in metal abundances between the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) affect most of the observable properties of the M supergiants in these galaxies; those in the SMC (which has the lowest metal abundance) have the earliest mean spectral type, while those of the Milky Way exhibit the latest mean spectral type. This is presently interpreted as a combination of two effects of differing metal abundance on the supergiant atmospheres: first, lower abundance stars of a given effective temperature have earlier MK spectral types due to reduced TiO abundance; second, the Hayashi track is shifted to hotter effective temperature at reduced metal abundance, thereby shifting the mean spectral type still earlier. The fact that the 10-micron excess decreases linearly with metal abundance suggests that mass loss rates are roughly the same for stars in all three galaxies, with the dust-to-gas ratio proportional to metal abundance.

Cited by

• Investigating episodic mass loss in evolved massive stars
• Red Supergiants -- The Other Side of the H-R Diagram
• Red Supergiants in the Milky Way and Nearby Galaxies
• Ruling out a massive asymptotic giant-branch star as the progenitor of supernova 2005cs
• UNVEILING THE σ-DISCREPANCY IN INFRARED-LUMINOUS MERGERS. I. DUST AND DYNAMICS,
• The Evolved Red Stellar Contents of the Sculptor Group Galaxies NGC 55, NGC 300, and NGC 7793
• The Near-Infrared Photometric Properties of Bright Giants in the Central Regions of the Galactic Bulge
• An Upper Mass Limit on a Red Supergiant Progenitor for the Type II-Plateau Supernova SN 2006my1
• The Red Supergiants in the Supermassive Stellar Cluster Westerlund 1
• High spectral resolution imaging of the dynamical atmosphere of the red supergiant Antares in the CO first overtone lines with VLTI/AMBER
• Really Cool Stars and the Star Formation History at the Galactic Center
• The Disk and Extraplanar Regions of NGC 55
• The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought

Related

• Abundances of the heavy elements in the Magellanic Clouds. I - Metal abundances of F-type supergiants
• The Coolest Stars in the Clouds: Unusual Red Supergiants in the Magellanic Clouds
• Investigating the metallicity dependence of the mass-loss rate relation of red supergiants
• Mass-loss Rate of Highly Evolved Stars in the Magellanic Clouds
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. IV. Calibration of Dust Depletions vs Abundance Ratios in the Milky Way and Magellanic Clouds and Application to Damped Lyman-alpha Systems