Spectrophotometry of 12 metal-poor galaxies : implications for the primordial helium abundance.

While all of the 12 galaxies for which relative emission line intensities are presented were expected to be metal-poor, on the basis of O III forbidden line strengths, all but two of the galaxies are found to be intrinsically faint, and likely to be gas-rich dwarf systems experiencing a transient burst of star formation. Attention was given at all stages of the analysis undertaken to the estimation of errors in the abundances derived for He, O, N, and Ne, relative to H. It was determined that all galaxies are, as expected, defficient in O by factors ranging from 3.5 to 20, and that the abundance of Ne correlates well with that of O, confirming the standard view that Ne, like O, is a primary product of stellar nucleosynthesis.