M17 SW molecular cloud

Journal Article · Wed Jun 01 04:00:00 EDT 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161028· OSTI ID:5471235

Thronson, Jr, H A; Lada, C J

We report new /sup 12/CO and /sup 13/CO observations of the massive molecular cloud associated with the giant M17 H II region. With a spatial resolution higher than previously reported, we find the brightest /sup 12/CO emission to lie in an elongated ridge, parallel and adjacent to a sharp ionization front at the apparent H II/H/sub 2/ interface. To within the positional uncertainties, the highest temperature /sup 12/CO emission is coincident with the brightest 100 ..mu..m emission. That this was not seen in earlier, lower resolution /sup 12/CO maps suggests a very steep molecular temperature gradient across the ionization front and emphasizes the uncertainties of using finite-sized beams. With the new data the molecular dissociation front is located. The radio molecular data also support the idea of a dusty molecular cloud that is largely externally heated by the exciting stars of the M17 H II region. These enormously luminous stars may be masking significant star-forming activity within the molecular cloud itself. The conditions in this cloud are suitable for star formation, although investigating this process in the infrared may be extremely difficult: /sup 13/CO column densities indicate significant absorption optical depths at wavelengths as long as approx.50 ..mu..m.

• Research Organization: Wyoming Infrared Observatory, University of Wyoming
• OSTI ID: 5471235
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 269:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC RADIO SOURCES
ELEMENTS
EMISSION SPECTRA
FUNCTIONS
H2 REGIONS
HYDROGEN
MAPS
NEBULAE
NONMETALS
OXIDES
OXYGEN COMPOUNDS
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS