2 Centimeter H/sub 2/CO emission in the rho Ophiuchi cloud

Journal Article · Mon Sep 15 04:00:00 EDT 1980 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/183346· OSTI ID:6684709

Loren, R B; Wootten, A; Sandqvist, A; Bernes, C

Strong emission in the 2 cm J-1K/sub 1/ =2/sub 12/--2/sub 11/ line of H/sub 2/CO has been found in the rho Oph dark cloud (rho Oph B). Previously this 2 cm H/sub 2/CO line has been detected in emission only in the warm (T/sub K/>50 K) clouds OMC-1 and OMC-2. Densities in excess of 10/sup 6/ cm/sup -3/ are required to drive this 2 cm line into emission. The 2 mm J-1K/sub 1/ =2/sub 12/--1/sub 11/ ortho-H/sub 2/CO emission line at rho Oph B appears to be self-reversed when compared to optically thin lines (e.g., H/sub 2//sup 13/CO). The dense rho Oph B core has a mass of approx.100 M/sub sun/ and an extinction of A/sub v/>200 mag similar to OMC-1 or OMC-2, but differs from them in temperature, being a cold region emitting strong lines of DCO/sup +/. While near- and far-infrared and radio continuum searches cover the rho Oph B region, no known sources are coincident with the region of 2 cm H/sub 2/CO emission. More sensitive searches are needed. The lack of observed signposts of star formation in an unusually dense cold region indicates rho Oph B may represent an earlier stage of cloud evolution than either the OMC-1 or OMC-2 regions.

• Research Organization: Millimeter Wave Observatory, Electrical Engineering Research Laboratory, The University of Texas at Austin
• OSTI ID: 6684709
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 240:3; ISSN AJLEA
• Country of Publication: United States
• Language: English

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640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALDEHYDES
CHEMICAL COMPOSITION
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COSMOCHEMISTRY
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
FORMALDEHYDE
INFRARED SPECTRA
INTERSTELLAR SPACE
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STAR ACCRETION
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