On the oxygen abundance in our Galaxy

Abstract

The compilation of published spectra of Galactic H II regions with available diagnostic [OIII]λ4363 line information has been carried out. Our list contains 71 individual measurements of 13 H II regions in the range of galactocentric distances from 6.6 to 14.8 kpc. The oxygen abundances in all the H II regions were recomputed in the same way, using the classic Te-method. The oxygen abundance at the solar galactocentric distance traced by those H II regions is in agreement with the oxygen abundance in the interstellar medium in the solar vicinity derived with high precision from the interstellar absorption lines towards stars. The derived radial oxygen abundance distribution was compared with that for H II regions from the Shaver et al. (1983) sample which is the basis of many models for the chemical evolution of our Galaxy. It was found that the original Shaver et al.'s oxygen abundances are overestimated by 0.2-0.3 dex. Oxygen abundances in H II regions from the Shaver et al. sample have been redetermined with the recently suggested P-method. The radial distribution of oxygen abundances from the Shaver et al. sample redetermined with the P-method is in agreement with our radial distribution of (O/H)Te abundances.