Modeling of G333. 6--0. 2 as a spherical H II region

Journal Article · Tue Feb 01 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160669· OSTI ID:5910199

Rubin, R H; Hollenbach, D J; Erickson, E F

We match the radio and infrared observations of the H II region G333.6--0.2 with a detailed spherical model with a density distribution that has a uniform-density core of radius rroughly-equal0.05 pc, a power-law intermediate zone, and a uniform-density halo. A stellar radiation field somewhat different from those predicted by available model atmospheres is required. Of the stellar models of Kurucz, the T/sub eff/ = 34,000 K and log g = 3.5 model best fits the observed ratio of helium to hydrogen recombination lines. However, this model predicts a S IV 10.5 ..mu..m line intensity which exceeds the observed value by a factor approx.10. A good fit to all the observations is obtained with a S/sup + +/ ionizing flux which is a factor approx.20 times less than predicted by the Kurucz atmosphere. Current model atmospheres may not be appropriate because a single stable star with T/sub eff/ = 34.000 K fails by at least an order of magnitude to produce the ionizing luminosity. Several arguments are presented against the hypothesis of a collection of stable stars. The large radius (Rroughly-equal60 R/sub sun/ ) required to fit the observations with a single ionizing source suggest a value of log g<3.5 and implies that the star may be undergoing radiatively driven mass loss. The method for modeling this H II region should serve as a useful guide to the modeling of other ionized nebulae.

• OSTI ID: 5910199
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 265:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics &amp; Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHEMICAL COMPOSITION
COSMIC RADIO SOURCES
H2 REGIONS
IONIZATION
MATHEMATICAL MODELS
NEBULAE
STAR MODELS
STELLAR ATMOSPHERES
STELLAR RADIATION