H/sub 2/O masers in circumstellar envelopes

Journal Article · Tue Dec 01 04:00:00 EST 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165869· OSTI ID:5438704

Lane, A P; Johnston, K J; Spencer, J H; Bowers, P F; Diamond, P J

The spatial structure of H/sub 2/O maser emission at 22.235 GHz for 12-late-type variable stars has been measured with a resolution of 0.07 arcsec. The H/sub 2/O maser regions of Mira variables range from 9 or less to 108 AU in total extent, while those of supergiant long-period variables are 300-720 AU in extent. The size of the H/sub 2/O maser regions of giants and supergiants is correlated with the stellar mass-loss rate. Several of the observed sources show evidence for nonspherical geometry in the distribution of their H/sub 2/O maser emission. The Mira variable IK Tau exhibits about 31 maser features over a total velocity range of 41 km/s. The spatial distribution of these features appears to be consistent with two spherical shells of radii 25 and 59 AU, both expanding at a velocity of 15.5 km/sec from the star. Evidence is found for density inhomogeneities and turbulent motions in the envelopes of both IK Tau and R Aql. 34 references.

• Research Organization: Boston Univ., MA (USA); E. O. Hulburt Center for Space Research, Washington, DC (USA); Sachs/Freeman Associates, Inc., Bowie, MD (USA); Max-Planck-Institut fuer Radioastronomie, Bonn, (Germany, F.R.)
• OSTI ID: 5438704
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 323; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
DISTRIBUTION
ELECTRONIC EQUIPMENT
EMISSION SPECTRA
EQUIPMENT
GIANT STARS
INTERFEROMETRY
MASERS
MASS TRANSFER
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MORPHOLOGY
SPATIAL DISTRIBUTION
SPECTRA
STARS
SUPERGIANT STARS
VARIABLE STARS