A new method of the determination ofplanetary nebula abundances and its application to the galactic halo nebulae.
Abstract
A novel method for determining the chemical composition of planetary nebulae is proposed. The correlations between the abundances of different ions obtained from photoionization models of planetary nebulae luminescence are used to take the observed ionization stages into account. Simple approximation expressions for determining the content of He/H, C/H, N/H, O/H, Ne/H, Mg/H, Si/H, and Ar/H are found. Refined values for the chemical composition of five planetary nebulae of the Galactic halo are given. The abundances of heavy elements found in these nebulae are an average of 25 percent less than those found by other authors. For nitrogen and sulphur this deviation reaches an average of 50 percent.
- Publication:
-
Astronomicheskii Zhurnal
- Pub Date:
- August 1993
- Bibcode:
- 1993AZh....70..691G
- Keywords:
-
- Planetary Nebulae;
- Chemical Composition;
- Galactic Halos;
- Photoionization;
- Nuclear Fusion;
- Star Formation;
- Astrophysics