2002/07/09 by M. Peimbert, Manuel Peimbert, Peimbert, Manuel +2
Chemical Engineering · Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics (astro-ph) #Atmospheric Ozone and Climate #Catalysis and Oxidation Reactions #FOS: Physical sciences #Spectroscopy and Laser Applications #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0207186
4 pages, conference on "Science with the GTC-10m Telescope", Granada, Spain, February, 2002
arxiv created 2002/07/09 · openalex publication_date 2002/07/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The determination of the heavy element abundances from giant extragalactic H II regions is based on collisionally excited lines. We argue that in the presence of temperature variations the abundances determined are lower limits to the real heavy element abundances. To determine the real abundances it is necessary to take into account the temperature variations present in these nebulae. We discuss the relevance of obtaining accurate line intensities of recombination lines of H, He, C, and O to determine the chemical composition of extragalactic H II regions. We suggest that Pagel's method to derive the O/H ratio should be calibrated by using recombination lines instead of photoionization models or abundances derived from collisionally excited lines.