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Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor Toward the Supergiant Star VY Canis MajorisWe report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 micron grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power lambda/delat.lambda of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of approximately 25 solar luminosity . In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the (sup 2)product(sub 1/2) (J = 5/2) left arrow (sup 2)product(sub 3/2) (J = 3/2) OH feature near 34.6 micron in absorption. Additional SWS observations of VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 7(sub 25)-6(sub 16) line at 29.8367 micron, the 4(sub 41)-3(sub 12) line at 31.7721 micron, and the 4(sub 32)-3(sub 03) line at 40.6909 micron. The higher spectral resolving power lambda/delta.lambda of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the "P Cygni" profiles that are characteristic of emission from an outflowing envelope.
Document ID
20000092482
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Neufeld, David A.
(Johns Hopkins Univ. Baltimore, MD United States)
Feuchtgruber, Helmut
(Max-Planck-Inst. fuer Extraterrestrische Physik Garching, Germany)
Harwit, Martin
(Harwit (Martin) Washington, DC United States)
Melnick, Gary J.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA United States)
Date Acquired
August 19, 2013
Publication Date
June 1, 1999
Publication Information
Publication: Astrophysical Journal
Publisher: American Astronomical Society
Volume: 517
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NAG5-3542
CONTRACT_GRANT: NAG5-3347
CONTRACT_GRANT: NAG5-3316
CONTRACT_GRANT: NAS5-30702
Distribution Limits
Public
Copyright
Other

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