Far-infrared emission lines of CO and OH in the Orion-KL molecular shock

Abstract

view Abstract Citations (98) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Far-infrared emission lines of CO and OH in the Orion-KL molecular shock. Watson, D. M. ; Genzel, R. ; Townes, C. H. ; Storey, J. W. V. 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 OH2 PI(3/2) JP = 7/2(-) yields 5/2(+) emission lines, as well as improved measurements of the CO J = 22 yields 21 and OH2 PI(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 H2 lines or the high velocity plateau component of the millimeter wave CO lines seen in this object. An H2 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 H2 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 H2 = 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/H2 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. Publication: The Astrophysical Journal Pub Date: November 1985 DOI: 10.1086/163612 Bibcode: 1985ApJ...298..316W Keywords: Carbon Dioxide; Far Infrared Radiation; Hydroxyl Emission; Line Spectra; Molecular Clouds; Orion Nebula; Interstellar Gas; Interstellar Matter; Nebulae; Astrophysics full text sources ADS | data products SIMBAD (1)