view Abstract Citations (48) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of H i Emission in the Circumstellar Envelope of Omicron Ceti (Mira) Bowers, P. F. ; Knapp, G. R. Abstract High-sensitivity 21 cm VLA observations of Mira (Omicron Cet), have resulted in the detection of H I in its circumstellar envelope. The central velocity is +46.4 + or - 0.3 km/s, and the expansion velocity is 4.6 + or - 0.3 km/s, in excellent agreement with values from CO observations. At a distance of 77 pc, the envelope radius is 160 arcsec or 1.8 x 10 to the 17th cm, the age (crossing time) is 1300 yr, and the total H I mass 0.0006 solar mass. The envelope appears to be roughly spherically symmetric, and the density gradient is shallower than 1/r2, the most plausible explanation appears to be photoproduction of H I from H2 by interstellar ultraviolet radiation. The observations then suggest that the total hydrogen loss rate from Omicron Cet is about 10 to the 7th solar mass/yr and that the wind is appproximately one-third atomic as it leaves the star. Consideration of the interaction between the wind and the interstellar medium suggests that the local interstellar density is about 0.03/ cu cm. Publication: The Astrophysical Journal Pub Date: September 1988 DOI: 10.1086/166655 Bibcode: 1988ApJ...332..299B Keywords: Giant Stars; H I Regions; Stellar Envelopes; Carbon Monoxide; Density Distribution; Hydrogen Atoms; Line Spectra; Stellar Mass; Stellar Winds; Velocity Distribution; Very Large Array (Vla); Astrophysics; RADIO SOURCES: 21 CM RADIATION; STARS: CIRCUMSTELLAR SHELLS; STARS: INDIVIDUAL CONSTELLATION NAME: O CETI; STARS: WINDS full text sources ADS | data products SIMBAD (3)