THE O++ H+ ABUNDANCE RATIO IN GASEOUS NEBULAE DERIVED FROM RECOMBINATION LINES/

We present O+2/H+ values for the Orion Nebula, M17, and NGC 6572 based on O II recombination lines, which are independent of the temperature structure of the observed nebulae. In the H II regions sampled (Orion and M17) the O+2/H+ values derived from O II recombination lines are about a factor of 2 higher than those derived from O III forbidden lin es. These differences can be accounted for by the presence of spatial temperature variations over the observed volumes. The abundances deriv ed from the recombination lines eliminate the O/H discrepancy between the stellar values and the H II region values of the solar neighborhoo d.