New Improved Calibration Relations for the Determination of Electron Temperatures and Oxygen and Nitrogen Abundances in H Ii Regions

New improved empirical calibrations for the determination of electron temperatures and oxygen and nitrogen abundances in H ii regions from the strong emission lines of oxygen, nitrogen, and sulfur are given. They are derived using spectra of H ii regions with measured electron temperatures as calibrating data. Calibration relations are given separately for three classes of H ii regions: cool, warm, and hot ones. Criteria for assigning a H ii region to one of these classes are suggested. We find that classification ambiguities arise only in the case of hot H ii regions with enhanced nitrogen abundances. The derived calibrations provide reliable abundances for H ii regions: the mean difference between oxygen abundances determined from the calibrations and Te-based oxygen abundances is ∼0.075 dex, while it is ∼0.05 dex for nitrogen abundances.