Abundances from emission lines in ionized nebulae

This contribution, presented at the 2016 conference on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas (ASOS12), shows how atomic physics contributes in the interpretation of emission-line spectra observed in astronomical nebulae, and discusses a few unsolved issues where atomic physics might play a role, although other possible explanations are indeed possible. It is limited to the determinations of chemical abundances, the most sought after information derived from emission lines.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author