The Near Circumstellar Environment of Miras

Abstract

Time series spectra were used to analyze the CO Δv=2 spectrum (2.3–2.5 μm) of 5 Miras and 1 SRa variable. A similar analysis previously was undertaken for the S-type Mira χ Cyg (Hinkle, Hall and Ridgway 1982). The Δv=2 spectrum of long period variables is complex with high excitation lines originating entirely in the (IR) photosphere and the lower excitation lines being formed through the photosphere and one or two extended atmospheric regions. The photospheric lines are characterized by large amplitude velocity and temperature changes with a mean excitation temperature of ~3000K (Hinkle, Scharlach and Hall 1984). In contrast, the extended atmospheric regions exhibit much smaller velocity changes plus lower and near stable excitation temperature.KeywordsStellar AtmosphereExcitation LineExcitation TemperatureSystemic VelocityPhotospheric LineThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.