Journal of The Korean Astronomical Society (천문학회지)
- Volume 22 Issue 2
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- Pages.127-140
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- 1989
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- 1225-4614(pISSN)
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- 2288-890X(eISSN)
EFFECTS OF THE DIFFUSE IONIZING RADIATION ON THE STRUCTURE OF HII REGIONS
- Hong, S.S. (Department of Astronomy, Seoul National University) ;
- Sung, H.I. (Department of Astronomy, Seoul National University)
- Published : 1989.12.31
Abstract
Problem of the diffuse radiation (DFR) transfer is solved exactly for pure hydrogen nebulae of uniform density, and accuracies of the on-the-spot (OTS) approximation are critically examined. For different values of density and spectral types of the central star, we have calculated the degree of ionization and the kinetic temperature of electrons as functions of distance from the central star, and compared them with the corresponding results of the OTS approximation. At most locations inside an HII region. the DFR ionizes considerable amount of hydrogen; therefore, the OTS approximation under-estimates the size of ionized regions. The exact treatment of the DFR transfer results in an about 10 to 20 percent increase in the classical
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