Spectroscopy of Red Variables and Other Luminous Red Stars

Abstract

Long period variable stars represent the most advanced stage of asymptotic giant branch evolution prior to planetary nebula ejection or catastrophic core collapse. In the Magellanic Clouds through study of the LPVs it has been possible to identify for the first time, stars on the AGB with luminosities right up to the AGB limit (Mbol ~ −7.1) providing direct evidence that the more massive AGB stars produce supernovae. Because the stars have well defined periods, knowledge of the temperature and luminosity enables the mass to be derived. This review will highlight spectroscopic observations of the LPVs and discuss what information they provide on nucleosynthesis on the AGB in stars of different mass.