Circumstellar gas and dust shells of M giants and supergiants

Abstract

view Abstract Citations (100) References (60) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Circumstellar gas and dust shells of M giants and supergiants. Hagen, W. Abstract Results are presented for an observational study of the circumstellar gas and dust shells of nine late-type giants and supergiants, based on a combination of optical spectroscopy of the circumstellar gas and IR observations of the circumstellar dust. It is found that the observed contrast in the 10-micron silicate feature is strongly affected by the dust temperature, that the dust grains must absorb more efficiently than terrestrial silicates at wavelengths shorter than 5 microns, and that the metals in the circumstellar shells of the M giants are almost entirely condensed onto grains. No correlation is seen between the observed amounts of circumstellar gas and dust. Physical conditions determined include particle number densities of 10 million to 100 million per cu cm at the inner edge of the circumstellar shells, expansion velocities of 7 to 10 km/s, and derived mass-loss rates of 10 to 20 billionths of a solar mass per yr for the late giants and 30 to 500 billionths of a solar mass per yr for the supergiants. Publication: The Astrophysical Journal Supplement Series Pub Date: September 1978 DOI: 10.1086/190542 Bibcode: 1978ApJS...38....1H Keywords: Giant Stars; Infrared Astronomy; M Stars; Stellar Envelopes; Stellar Mass Ejection; Stellar Spectrophotometry; Supergiant Stars; Gas Density; Infrared Spectra; Interstellar Matter; Late Stars; Astrophysics; Circumstellar Shells:M Giants; Circumstellar Shells:Supergiants; M Giants:Mass Loss; Mass Loss:Supergiants full text sources ADS | data products SIMBAD (9)