Forbidden lines from inhomogeneous nebulae: the case of a density distribution N ∝ r-2.
Abstract
The formation of forbidden lines in a nebula with density inversely proportional to the square of r is considered. We show that the forbidden-line-intensity ratios (FLIR) may mimic those of constant density nebulae, whose physical conditions differ considerably from the actual ones. The limits of a FLIR analysis in terms of a constant density model are discussed. We find that a self-consistent analysis is necessary for a correct interpretation of FLIR data, otherwise quite misleading results may be obtained: i.e., overestimate of the minimum density and the electron temperature, underestimate of the maximum density and the abundances relative to hydrogen, ad hoc ionization structure.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1975
- Bibcode:
- 1975A&A....43...93P
- Keywords:
-
- Density Distribution;
- Electron Density (Concentration);
- Electron Energy;
- Forbidden Bands;
- Nebulae;
- Abundance;
- Astronomical Models;
- Gas Ionization;
- Hydrogen;
- Temperature Distribution;
- Astrophysics