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

Abstract

We suggest a new way to establish the relation between the electron temperature (3 within the [OIII] zone and the electron temperature t3 within the [O II] zone in high-metallicity (12 + log(O/H) > 8.25) H II regions. The t2-t3 diagram is constructed by applying our method to a sample of 372 H II regions. We find that the correlation between t2 and t3 is tight and can be approximated by a linear expression. The new t2-t3 relation can be used to determine t2 and accurate abundances in high-metallicity H II regions with a measured t3. It can also be used in conjunction with the ff relation for the determination of t3 and t2 and oxygen abundances in high-metallicity HII regions, where the [OIII]λ4363 auroral line is not detected. The derived t2-t3 relation is independent of photoionization models of HII regions. © 2006 RAS.