The results of optical spectroscopy of H II regions in a sample of southern dwarf irregulars consisting of five dwarf galaxies in the Centaurus A group , four dwarfs in the Sculptor group , and eight additional dwarf galaxies are presented .
Oxygen abundances are derived using the direct method where [ O III ] \lambda 4363 is detected ; otherwise , abundances are derived with the bright-line method using the McGaugh and the Pilyugin calibrations .
ESO358 - G060 has the lowest oxygen abundance ( 12 + log ( O/H ) = 7.32 ) , which is comparable to the value for the second most metal-poor galaxy known ( SBS 0335 - 052 ) .
In all , new oxygen abundances are reported for nine dwarf galaxies ; updated values are presented for the remaining galaxies .
Derived oxygen abundances are in the range from 3 % to 26 % of the solar value .
Oxygen abundances for dwarfs in the southern sample are consistent with the metallicity-luminosity relationship defined by a control sample of dwarf irregulars with [ O III ] \lambda 4363 abundances and well-measured distances .
However , NGC 5264 appears to have an ( upper branch ) oxygen abundance approximately two to three times higher than other dwarfs at similar luminosities .
Nitrogen-to-oxygen and neon-to-oxygen abundance ratios are also reported ; in particular , IC 1613 and IC 5152 show elevated nitrogen-to-oxygen ratios for their oxygen abundances .