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Detection of a weak maser emission pedestal associated with the SiO maserResults are reported for high-spectral-resolution observations of the v = 1, J = 1-0 SiO maser sources at 43,122.027 MHz (6.95 mm wavelength) associated with the variable stars Omega Cet, NML Tau, VY CMa, R Leo, W Hya, VX Sgr, NML Cyg, and R Cas. A weak underlying maser emission pedestal is clearly observed in the spectra of all but NML Cyg and R Cas. The data indicate that the underlying pedestal of SiO emission appears to originate in a shell-like region around the star, has a thermal appearance even though it must be due to weak maser emission, and appears to be part of the spectral signature of SiO maser emission from late-type stars. It is found that the center velocities of the pedestals may be used to determine stellar radial velocities. Observations of large-scale time variations in the intensity of the Ori A SiO maser and the detection of weak maser pedestals associated with each of the two strong emission-feature groups in Orion are also discussed. It is suggested that the Orion molecular cloud might contain two late-type long-period variable stars that may be semiregular variables.
Document ID
19780065564
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Snyder, L. E.
(Illinois, University Urbana, Ill., United States)
Dickinson, D. F.
(Harvard College Observatory and Smithsonian Astrophysical Observatory, Center for Astrophysics, Cambridge Mass., United States)
Brown, L. W.
(Illinois Univ. Urbana, IL, United States)
Buhl, D.
(NASA Goddard Space Flight Center Laboratory for Extraterrestrial Physics, Greenbelt, Md., United States)
Date Acquired
August 9, 2013
Publication Date
September 1, 1978
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
78A49473
Funding Number(s)
CONTRACT_GRANT: NSF AST-77-01345
Distribution Limits
Public
Copyright
Other

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