Temperature fluctuations in photoionized nebulae. II. The effect of inhomogeneous abundances

Recent abundance determinations based on recombination lines in several emi ssion-line nebulae yield ionic abundances several times larger than those d erived from forbidden lines. These results cast uncertainty over all abunda nce determinations in such objects. One possible explanation for these disc repancies frequently cited in the literature is the presence of chemical in homogeneities. We have run a series of photoionization models to examine wh at effect such inhomogeneities will have on the resulting temperature struc ture of nebulae. We then derive abundances from these models, utilizing Pei mbert's t(2) formalism. Our results suggest that, although chemical inhomog eneities may produce nonnegligible biases in abundance determinations in a small number of objects, it is highly unlikely that they can resolve the ob served discrepancy for most nebulae. We also stress the importance of conti nued high spatial resolution observations in nebulae to clarify the presenc e or absence of inhomogeneities in gaseous nebulae.