A Large-Scale Survey of Neutron-Capture Element Abundances in Planetary Nebulae

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dc.creatorSterling, N. C.
dc.creatorDinerstein, Harriet L.
dc.creatorKallman, T. R.
dc.date2007-08-09
dc.date.accessioned2026-07-07T08:22:57Z
dc.date.available2026-07-07T08:22:57Z
dc.descriptionWe present results from the first large-scale survey of neutron(n)-capture element abundances in planetary nebulae (PNe). This survey was motivated by the fact that a PN may be enriched in n-capture elements if its progenitor star experienced s-process nucleosynthesis during the asymptotic giant branch (AGB) phase. [Kr III] 2.199 and/or [Se IV] 2.287 $μ$m were detected in 81 PNe out of 120 PNe, for a detection rate of nearly 70%. We derive Se and Kr abundances or upper limits using ionization correction factors derived from photoionization models. A significant range is found in the Se and Kr abundances, from near solar (no enrichment), to enriched by a factor of ten. Our survey has increased the number of PNe with known n-capture element abundances by an order of magnitude, enabling us to explore correlations between s-process enrichments and other nebular and central star properties. In particular, the Se and Kr enrichments display a positive correlation with nebular C/O ratios, as theoretically expected. Peimbert Type I PNe and bipolar PNe, whose progenitors are believed to be intermediate-mass stars (>3-4 M_sun), exhibit little or no s-process enrichment. Interestingly, PNe with H-deficient [WC] central stars do not exhibit systematically larger s-process enrichments than other PNe, despite the fact that their central stars are enriched in C and probably n-capture elements. Finally, the few PNe in our sample with known or probable binary central star systems exhibit little s-process enrichment, which may be explained if binary interactions truncated their AGB phases. We also briefly discuss a new observational program to detect optical emission lines of n-capture elements, and new atomic data calculations that will greatly improve the accuracy of n-capture element abundance determinations in PNe.
dc.description8 pages, 2 figures. To appear in "Asymmetrical Planetary Nebulae IV," eds. R. L. M. Corradi, A. Manchado & N. Soker
dc.identifierhttps://arxiv.org/abs/0708.1323
dc.identifierhttp://arxiv.org/abs/0708.1323
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/135829
dc.subjectAstrophysics
dc.titleA Large-Scale Survey of Neutron-Capture Element Abundances in Planetary Nebulae
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