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The gaseous component of the disk around Beta PictorisOptical spectra of alpha Lyr, alpha PsA, and beta Pic have been obtained at a velocity resolution of 3 km/s. No circumstellar absorption lines of Ca II or Na I are detected toward alpha Lyr or alpha PsA at sensitive limits. In the favorable case of beta Pic, where the circumstellar disk imaged by Smith and Terrile (1984) is seen nearly edge-on, a strong, narrow, circumstellar Ca II K absorption line previously reported by Slettebak (1982) and weaker, still narrower circumstellar Na I D lines are detected. Negative results of high sensitivity also are obtained for the Ca I 4226 A and CH(+) 4232 A lines, along with upper limits on the Zn II 2026, 2062 A doublet from archival IUE spectra. Under assumptions which agree with other well-established observations of the gaseous abundances of calcium and zinc, the total gaseous column density of hydrogen along a radius of the circumstellar disk is between 10 to the 18th and 4 x 10 to the 20th/sq cm. Within the boundaries of the dust disk detected by Smith and Terrile (1984) the total gaseous mass then is less than about 2, or less than 1 percent of the mass of the planetary system. A simplified model of the density distribution in the gaseous disk yields a characteristic total density n(H) of about 100,000/cu cm, which exceeds that of all interplanetary gas at earth's position by a factor of about 10,000.
Document ID
19850054889
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hobbs, L. M.
(Yerkes Observatory Williams Bay, WI, United States)
Vidal-Madjar, A.
(Yerkes Observatory Williams Bay, WI, United States)
Ferlet, R.
(CNRS Institut d'Astrophysique, Paris, France)
Albert, C. E.
(U.S. Naval Academy Annapolis, MD, United States)
Gry, C.
(ESA Astrophysics Div., Noordwijk, Netherlands)
Date Acquired
August 12, 2013
Publication Date
June 1, 1985
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters to the Editor
Volume: 293
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
85A37040
Funding Number(s)
CONTRACT_GRANT: NGR-14-001-147
Distribution Limits
Public
Copyright
Other

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