Physical Properties of Red Supergiants

Philip Massey (1), Bertrand Plez (2), Emily M. Levesque (3), K. A. G. Olsen (4), David R Silva (5), and Geoffery C. Clayton (6)

(1) Lowell Observatory; (2) GRAAL, Universite de Montellier II, CNRS; (3) Instiute for Astronomy, University of Hawaii; (4) Gemini Science Center, NOAO; (5) Thirty Meter Telescope; (6) Dept of Physics and Astronomy, Louisiana State University

Red supergiants (RSGs) are an evolved stage in the life of intermediate massive stars ($<25M_odot$). For many years their location in the H-R diagram was at variance with the evolutionary models. Using the MARCS stellar atmospheres, we have determined new effective temperatures and bolometric luminosities for RSGs in the Milky Way, LMC, and SMC, and our work has resulted in much better agreement with the evolutionary models. We have also found evidence of significant visual extinctiondue to circumstellar dust. Although in the Milky Way the RSGs contribute only a small fraction($<$1%) of the dust to the interstellar medium (ISM), in starburst galaxies or galaxies at large look-back times, we expect that RSGs may be the main dust source. We are in the process ofextending this work now to RSGs of higher and lower metallicities using the galaxies M31 and WLM.

Reference: to appear in The Biggest, Baddest, Coolest Stars, ASP Conf Series, ed. D. Luttermoser, B. Smith, and R. Stencel
Status: Conference proceedings