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Author Icke, V. ♦ Gatley, I. ♦ israel, F. P.
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 ♦ REGIONS ♦ INFRARED RADIATION ♦ RADIOWAVE RADIATION ♦ COSMIC DUST ♦ ELECTROMAGNETIC RADIATION ♦ EMISSIVITY ♦ INTERSTELLAR GRAINS ♦ IONIZATION ♦ LYMAN LINES ♦ PHOTONS ♦ STARS ♦ COSMIC RADIO SOURCES ♦ DUSTS ♦ ELEMENTARY PARTICLES ♦ MASSLESS PARTICLES ♦ OPTICAL PROPERTIES ♦ PARTICLES ♦ PHYSICAL PROPERTIES ♦ RADIATIONS ♦ SURFACE PROPERTIES ♦ Astrophysics & Cosmology- Galaxies
Abstract We present detailed calculations for the observational appearance of nonspherical Stroemgren regions at radio and infrared wavelengths. The computations are made feasible by two assumptions, namely (1) no stellar photon leaves the solid angle within which it was emitted, and (2) the radiation spectrum can be represented by three delta functions corresponding to Lyman continuum, Lyman alpha, and softer radiation, respectively. On the basis of these calculations we show models for the H II blisters M17 A and 30 Doradus, and also first order parameters for a sample of other well-studied galactic H II regions. From all this, we conclude that the observations are well explained by an ionizing object in a density gradient, without the need for peculiar dust properties or distribution. In particular, we are able to reproduce the displacement of the emission maxima in the direction in which the density of the ambient medium increases. Hereby we find further support for the blister picture and, indirectly, for models of star formation that describe the birth of massive stars near the outer parts of dense clouds.
Educational Use Research
Learning Resource Type Article
Publisher Date 1980-03-15
Publisher Department California Institute of Technologt and University of Minnesota, Minneapolis
Publisher Place United States
Journal Astrophys. J.
Volume Number 236
Issue Number 3
Organization California Institute of Technologt and University of Minnesota, Minneapolis


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