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Observational tests for H II region models - A 'champagne party'

Journal Article:

Abstract

Observations of several neighboring H II regions associated with a molecular cloud were performed in order to test the champagne model of H II region-molecular cloud interaction leading to the supersonic expansion of molecular cloud gas. Nine different positions in the Gum 61 nebula were observed using an image dissector scanner attached to a 3.6-m telescope, and it is found that the area corresponds to a low excitation, high density nebula, with electron densities ranging between 1400 and 2800/cu cm and larger along the boundary of the ionized gas. An observed increase in pressure and density located in an interior region of the nebula is interpreted in terms of an area between two rarefaction waves generated together with a strong isothermal shock, responsible for the champagne-like streaming, by a pressure discontinuity between the ionized molecular cloud in which star formation takes place and the intercloud gas. It is noted that a velocity field determination would provide the key in understanding the evolution of such a region.
Publication Date:
Sep 01, 1979
Product Type:
Journal Article
Reference Number:
EDB-82-167020
Resource Relation:
Journal Name: ESO Messenger; (Germany, Federal Republic of)
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; H2 REGIONS; COSMIC GASES; COSMOLOGICAL MODELS; NEBULAE; ELECTRON DENSITY; EXPANSION; ASTROPHYSICS; HYDROGEN IONS 1 PLUS; IONIZED GASES; CATIONS; CHARGED PARTICLES; COSMIC RADIO SOURCES; FLUIDS; GASES; HYDROGEN IONS; IONS; MATHEMATICAL MODELS; 640105* - Astrophysics & Cosmology- Galaxies
OSTI ID:
6927192
Research Organizations:
European Southern Observatory, Geneva, Switzerland
Country of Origin:
Germany
Language:
English
Submitting Site:
HEDB
Size:
Pages: 12-14
Announcement Date:

Journal Article:

Citation Formats

Alloin, D, and Tenorio-Tagle, G. Observational tests for H II region models - A 'champagne party'. Germany: N. p., 1979. Web.
Alloin, D, & Tenorio-Tagle, G. Observational tests for H II region models - A 'champagne party'. Germany.
Alloin, D, and Tenorio-Tagle, G. 1979. "Observational tests for H II region models - A 'champagne party'." Germany.
@misc{etde_6927192,
title = {Observational tests for H II region models - A 'champagne party'}
author = {Alloin, D, and Tenorio-Tagle, G}
abstractNote = {Observations of several neighboring H II regions associated with a molecular cloud were performed in order to test the champagne model of H II region-molecular cloud interaction leading to the supersonic expansion of molecular cloud gas. Nine different positions in the Gum 61 nebula were observed using an image dissector scanner attached to a 3.6-m telescope, and it is found that the area corresponds to a low excitation, high density nebula, with electron densities ranging between 1400 and 2800/cu cm and larger along the boundary of the ionized gas. An observed increase in pressure and density located in an interior region of the nebula is interpreted in terms of an area between two rarefaction waves generated together with a strong isothermal shock, responsible for the champagne-like streaming, by a pressure discontinuity between the ionized molecular cloud in which star formation takes place and the intercloud gas. It is noted that a velocity field determination would provide the key in understanding the evolution of such a region.}
journal = {ESO Messenger; (Germany, Federal Republic of)}
journal type = {AC}
place = {Germany}
year = {1979}
month = {Sep}
}