We present a tutorial on the determination of the physical conditions and chemical abundances in gaseous nebulae. We also include a brief review of recent results on the study of gaseous nebulae, their relevance for the study of stellar evolution, galactic chemical evolution, and the evolution of the universe. One of the most important problems in abundance determinations is the existence of a discrepancy between the abundances determined with collisionally excited lines and those determined by recombination lines: this is called abundance discrepancy factor (ADF) problem, and we review results related to it. Finally, we discuss the possible reasons for the large t 2 values observed in gaseous nebulae.
Publications of the Astronomical Society of the Pacific
- Pub Date:
- August 2017
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- 29 pages, six figures. Accepted for publication as invited tutorial in PASP