On the electron temperature determination in high-metallicity H ii 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.