Spectroscopic study of five Mira stars

Abstract

Mira stars are popular with amateur astronomers because they are generally bright and their pulsations produce large changes in brightness. This also means they are eminently suitable to study using spectroscopy. We report here on spectroscopic observations of five Mira stars: RY Cep, SU Cam, T Cep, V667 Cas and OR Cep. We describe the lifecycle of a Mira star and explain how the carbon-oxygen balance in its atmosphere determines its spectral classification. Atmospheric pulsations in these stars produce shocks which generate Balmer emission. We present graphically their different spectral behaviours and development of emission lines.