On the electron temperature determination in high-metallicity HII regions

Abstract

The problem of determination of the electron temperature t_2 in the OII zone of high-metallicity HII region was examined. It was shown that the ratio of nebular to auroral nitrogen line intensities, which is an indicator of the electron temperature t_2, can be expressed in terms of the nebular line intensities of oxygen. This solves the problem of the determination of the electron temperature t_2, since the oxygen nebular lines are strong and, consequently, are readily observable. A relation between electron temperatures in the OII and OIII zones in high-metallicity HII regions was studied. It was found that there is no one-to-one correspondance between t_2 and t_3 temperatures. Instead the t_2 - t_3 relation is dependent on excitation parameter.