On the electron temperature determination in high-metallicity HII regions

The problem of determination of the electron temperature t(2) in the O+ zone of high-metallicity H-II regions is examined. It is 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 O+ and O++ zones in high-metallicity H-II regions is studied. It is found that there is no one-to-one correspondence between t(2) and t(3) temperatures. Instead the t(2)-t(3) relation is dependent on the excitation parameter.