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dc.creatorSterling, N. C.en_US
dc.creatorDinerstein, Harriet L.en_US
dc.date.accessioned2016-10-28T19:37:16Z
dc.date.available2016-10-28T19:37:16Z
dc.date.issued2008-01en_US
dc.identifierdoi:10.15781/T2D50G09N
dc.identifier.citationSterling, N. C., and Harriet L. Dinerstein. "The abundances of light neutron-capture elements in planetary nebulae. II. s-process enrichments and interpretation." The Astrophysical Journal Supplement Series, Vol. 174, No. 1 (Jan., 2008): 158.en_US
dc.identifier.issn0067-0049en_US
dc.identifier.urihttp://hdl.handle.net/2152/43057
dc.description.abstractWe present the results of a large-scale survey of neutron(n)-capture elements in Galactic planetary nebulae (PNe), undertaken to study enrichments from s-process nucleosynthesis in their progenitor stars. From new K-band observations of over 100 PNe supplemented by data from the literature, we have detected the emission lines [Kr III] 2.199 mu m and/or [Se IV] 2.287 mu m in 81 of 120 objects. We determine Se and Kr elemental abundances, employing ionization correction formulae derived in the first paper of this series. We find a significant range in Se and Kr abundances, from near solar (no enrichment) to enhanced by > 1.0 dex relative to solar, which we interpret as self-enrichment due to in situ s-process nucleosynthesis. Kr tends to be more strongly enriched than Se; in 18 objects exhibiting both Se and Kr emission, we find that [Kr/Se] = 0.5 +/- 0.2. Our survey has increased the number of PNe with n-capture element abundance determinations by a factor of 10, enabling us for the first time to search for correlations with other nebular properties. As expected, we find a positive correlation between s-process enrichments and the C/O ratio. Type I and bipolar PNe, which arise from intermediate-mass progenitors (> 3-4 M-circle dot), exhibit little to no s-process enrichments. Finally, PNe with H-deficient Wolf-Rayet central stars do not exhibit systematically larger s-process enrichments than objects with H-rich nuclei. Overall, 44% of the PNe in our sample display significant s-process enrichments (> 0.3 dex). Using an empirical PN luminosity function to correct for incompleteness, we estimate that the true fraction of s-process enriched Galactic PNe is at least 20%.en_US
dc.description.sponsorshipNSF AST 97-31156, AST 04-06809en_US
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectinfrared : generalen_US
dc.subjectnuclear reactions, nucleosynthesis, abundancesen_US
dc.subjectplanetary nebulae : generalen_US
dc.subjectstars : agb and post-agben_US
dc.subjectstars : evolutionen_US
dc.subjectasymptotic giant branchen_US
dc.subjectwolf-rayet nucleien_US
dc.subjectintermediate-mass starsen_US
dc.subjectwcen_US
dc.subjectcentral starsen_US
dc.subjectoptical recombination linesen_US
dc.subjectstatistical distance scaleen_US
dc.subjectnear-infrared spectroscopyen_US
dc.subjectenergy-balance temperatureen_US
dc.subjecthubble-space-telescopeen_US
dc.subjectdust emission featuresen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleThe Abundances of Light Neutron-Capture Elements in Planetary Nebulae. II. S-Process Enrichments and Interpretationen_US
dc.typeReviewen_US
dc.description.departmentAstronomyen_US
dc.rights.restrictionOpenen_US
dc.identifier.doi10.1086/520845en_US
dc.contributor.utaustinauthorSterling, N. C.en_US
dc.contributor.utaustinauthorDinerstein, Harriet L.en_US
dc.relation.ispartofserialAstrophysical Journal Supplement Seriesen_US


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