Observations of Mass Loss and Circumstellar Matter around Cool Carbon Stars

Abstract

Spectroscopy and infrared photometry of carbon stars show three distinct forms of circumstellar matter. IRAS 12311-3509 probably has an edge-on disk and the spectrum is dominated by resonance emission from atoms and molecules in the vicinity. The long-period variables V Hya and R Lep are undergoing deep fadings, apparently caused by dust formation around the star, while variable emission from circumstellar gas is seen. The semiregular variable T Mus showed absorption bands from very cool material during an unusual episode in 1994.