Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008apjs..174..158s&link_type=abstract
The Astrophysical Journal Supplement Series, Volume 174, Issue 1, pp. 158-201.
Astronomy and Astrophysics
Astronomy
30
Infrared: General, Nuclear Reactions, Nucleosynthesis, Abundances, Ism: Planetary Nebulae: General, Stars: Agb And Post-Agb, Stars: Evolution
Scientific paper
We 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 μm and/or [Se IV] 2.287 μm 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 Msolar), 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%.
This paper includes data taken at the McDonald Observatory of the University of Texas at Austin.
Dinerstein Harriet L.
Sterling Nicholas C.
No associations
LandOfFree
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. II. s-Process Enrichments and Interpretation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. II. s-Process Enrichments and Interpretation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. II. s-Process Enrichments and Interpretation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1594854