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Session 49 - Starburst Galaxies.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center
Speculation that massive star winds and supernovae create short--term localized enrichments of heavy elements in low-metallicity extragalactic H II regions (Kunth amp; Sargent 1986, ApJ, 300, 496; Pagel amp; Terlevich 1986, PASP, 98, 1005) has so far received evidential support in only a limited number of cases. Knowledge of the extent to which H II regions are ``self-polluted'' on short time scales with the nucleosynthesis products of massive stars will have important implications for studies of galactic chemical evolution and primordial nucleosynthesis which depend on abundance measurements in such environments. As part of a larger study of localized enrichment in HII regions, we present an optical spectroscopic search for localized abundance fluctuations in the irregular galaxy NGC 4214 which has multiple young starburst clusters and a significant population of Wolf-Rayet stars. Our initial analysis indicates no significant abundance enhancements in the vicinity of any of the young starburst knots with or without Wolf-Rayet stars. Yet, other Wolf-Rayet galaxies show evidence for enhancements of nitrogen and helium, most notably NGC 5253 (Walsh amp; Roy 1989, MNRAS, 239, 297). Scenarios for such abundance enhancements are discussed.
Program listing for Tuesday