Volume 369, Number 2, April II 2001
|Page(s)||594 - 604|
|Published online||15 April 2001|
On the oxygen abundance determination in HII regions.
Main Astronomical Observatory of National Academy of Sciences of Ukraine, Goloseevo, 03680 Kiev-127, Ukraine
Accepted: 22 December 2000
This is our second paper devoted to the problem of line intensity -oxygen abundance calibration starting from the idea of McGaugh ([CITE]) that the strong oxygen lines ( and ) contain the necessary information to determine accurate abundances in HII regions. In the previous study (Pilyugin 2000) the corresponding relations were obtained for the low-metallicity HII regions (, the lower branch of the O/H -R23 diagram). The high-metallicity HII regions (, the upper branch of the O/H -R23 diagram) are considered in the present study. A relation of the type ) between oxygen abundance and the value of abundance index R23, introduced by Pagel et al. ([CITE]), and the excitation parameter P (which is defined here as the contribution of the radiation in lines to the "total" oxygen radiation) has been derived empirically using the available oxygen abundances determined via measurement of a temperature-sensitive line ratio [OIII]4959,5007/[OIII]4363 (Te-method). By comparing oxygen abundances in high-metallicity HII regions derived with the Te-method and those derived with the suggested relations (P-method), it was found that the precision of oxygen abundance determination with the P-method is around 0.1 dex (the mean difference for the 38 HII regions considered is ~0.08 dex) and is comparable to that of the Te-method. A relation of the type ) between electron temperature and the values of abundance index R23 and the excitation parameter P was derived empirically using the available electron temperatures determined via measurement of temperature-sensitive line ratios. The maximum value of differences between electron temperatures determined via measurement of temperature-sensitive line ratios and those derived with the suggested relation is around 1000 K for HII regions considered here, the mean value of differences for 38 HII regions is ~500 K, which is the same order of magnitude as the uncertainties of electron temperature determinations in high-metallicity HII regions via measured temperature-sensitive line ratios.
Key words: ISM: HII regions / galaxies: abundances / galaxies: ISM / galaxies: spiral
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.