Ionization Equilibrium in Isolated Hydrogen II Regions.
Abstract
Theoretical ionization equilibrium models are combined with Copernicus ultraviolet observations to study a particular H II region component in the absorption spectra of (lamda) Sco and (upsilon) Sco. The (lamda) Sco observations imply that the region is characterized by T (DBLTURN) 10('4)(DEGREES)K, n(,H) (DBLTURN) .2 cm('-3), and an extent along the line of sight of approximately 16 parsecs. Ionization equilibrium calculations incorporating recent theoretical values for photoionization cross sections and for rate coefficients of charge transfer are used to determine a separation of approximately 5 parsecs between the H II region and the ionizing star. Comparison with (upsilon) Sco observations suggest that small-scale clumps are present, with density varying by a factor of two or more over a scale of one parsec.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1983
- Bibcode:
- 1983PhDT.........1E
- Keywords:
-
- Physics: Astronomy and Astrophysics;
- Absorption Spectra;
- Hydrogen;
- Ionization;
- Stellar Spectra;
- H Ii Regions;
- Interstellar Chemistry;
- Ionization Cross Sections;
- Oao 3;
- Ultraviolet Astronomy;
- Astrophysics