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Author Watson, D. M. ♦ Genzel, R. ♦ Townes, C. H. ♦ Storey, J. W. V.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ NEBULAE ♦ CHEMICAL COMPOSITION ♦ ABUNDANCE ♦ CARBON DIOXIDE ♦ EMISSION SPECTRA ♦ FAR INFRARED RADIATION ♦ CARBON COMPOUNDS ♦ CARBON OXIDES ♦ CHALCOGENIDES ♦ ELECTROMAGNETIC RADIATION ♦ INFRARED RADIATION ♦ OXIDES ♦ OXYGEN COMPOUNDS ♦ RADIATIONS ♦ SPECTRA ♦ Astrophysics & Cosmology- Galaxies
Abstract Observations of far infrared rotational emission lines which arise in the shocked gas associted with Orion-Kl are presented, including detections of the CO J = 34 yields 33, J = 31 yields 30, J = 26 yields 25, and OH sup 2 PI sub (3/2) J sup P = 7/2(-) yields 5/2(+) emission lines, as well as improved measurements of the CO J = 22 yields 21 and OH sup 2 PI sub (3/2) J = 5/2 yields 3/2 lines. These lines are observed to have velocity widths of Del V approx. 20 to 30 km/sec, somewhat less than either the 2 micro H sub 2 lines or the high velocity plateau component of the millimeter wave CO lines seen in this object. An H sub 2 column density of aprox. 3 x 10 to the 21st power, a total mass of approx. 1 solar mass and characteristic temperature and density T approx. 750 K and approx. 2 x 10 to the 6th power per cu cm can be derived from the CO intensities. The density is too low by at least an order of magnitude for the observed infrared H sub 2 and far infrared CO emission to be accounted for by a purely hydrodynamic shock, and support is lent to hydromagnetic shock models. From the present measurements, the relative abundance of CO is estimated to be CO H sub 2 = 1.2 x .0001, corresponding to 20 percent of the cosmic abundance of C existing in the form of CO. The average relative abundance of OH in the shocked gas is O/H sub 2 or = 5 x 10 to the -7th power. An upper limit to the intensity of the HD J - 1 yields 0 line is used to derive an upper limit of tau or = 3 for the D/H relative abundance in the Orion cloud core. 61 references.
Educational Use Research
Learning Resource Type Article
Publisher Date 1985-11-01
Publisher Department California Univ., Berkeley ♦ California Institute of Technology, Pasadena ♦ Anglo-Australian Observatory, Epping ♦ New South Wales Univ., Kensington, Australia
Publisher Place United States
Journal Astrophys. J.
Volume Number 298
Organization California Univ., Berkeley ♦ California Institute of Technology, Pasadena ♦ Anglo-Australian Observatory, Epping ♦ New South Wales Univ., Kensington, Australia


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