On the relation between electron temperatures in the O+ and O++ zones in high-metallicity H ii regions

We suggest a new way to establish the relation between the electron temperature t 3 within the [O iii] zone and the electron temperature t 2 within the [O ii] zone in high-metallicity (12 + log(O/H) > 8.25) H ii regions. The t 2-t 3 diagram is constructed by applying our method to a sample of 372 H ii regions. We find that the correlation between t 2 and t 3 is tight and can be approximated by a linear expression. The new t 2-t 3 relation can be used to determine t 2 and accurate abundances in high-metallicity H ii regions with a measured t 3. It can also be used in conjunction with the ff relation for the determination of t 3 and t 2 and oxygen abundances in high-metallicity H ii regions, where the [O iii]λ4363 auroral line is not detected. The derived t 2-t 3 relation is independent of photoionization models of H ii regions.