TY - GEN
T1 - Advances in atomic data for neutron-capture elements
AU - Sterling, Nicholas C.
AU - Witthoeft, Michael C.
AU - Esteves, David A.
AU - Stancil, Phillip C.
AU - Kilcoyne, A. L.David
AU - Bilodeau, Rene C.
AU - Aguilar, Alejandro
PY - 2011/7
Y1 - 2011/7
N2 - Neutron(n)-capture elements (atomic number Z > 30), which can be produced in planetary nebula (PN) progenitor stars via s-process nucleosynthesis, have been detected in nearly 100 PNe. This demonstrates that nebular spectroscopy is a potentially powerful tool for studying the production and chemical evolution of trans-iron elements. However, significant challenges must be addressed before this goal can be achieved. One of the most substantial hurdles is the lack of atomic data for n-capture elements, particularly that needed to solve for their ionization equilibrium (and hence to convert ionic abundances to elemental abundances). To address this need, we have computed photoionization cross sections and radiative and dielectronic recombination rate coefficients for the first six ions of Se and Kr. The calculations were benchmarked against experimental photoionization cross section measurements. In addition, we computed charge transfer (CT) rate coefficients for ions of six n-capture elements. These efforts will enable the accurate determination of nebular Se and Kr abundances, allowing robust investigations of s-process enrichments in PNe.
AB - Neutron(n)-capture elements (atomic number Z > 30), which can be produced in planetary nebula (PN) progenitor stars via s-process nucleosynthesis, have been detected in nearly 100 PNe. This demonstrates that nebular spectroscopy is a potentially powerful tool for studying the production and chemical evolution of trans-iron elements. However, significant challenges must be addressed before this goal can be achieved. One of the most substantial hurdles is the lack of atomic data for n-capture elements, particularly that needed to solve for their ionization equilibrium (and hence to convert ionic abundances to elemental abundances). To address this need, we have computed photoionization cross sections and radiative and dielectronic recombination rate coefficients for the first six ions of Se and Kr. The calculations were benchmarked against experimental photoionization cross section measurements. In addition, we computed charge transfer (CT) rate coefficients for ions of six n-capture elements. These efforts will enable the accurate determination of nebular Se and Kr abundances, allowing robust investigations of s-process enrichments in PNe.
KW - atomic data
KW - planetary nebulae: general
KW - stars: AGB and post-AGB
UR - http://www.scopus.com/inward/record.url?scp=84865786683&partnerID=8YFLogxK
U2 - 10.1017/S1743921312012148
DO - 10.1017/S1743921312012148
M3 - Conference contribution
AN - SCOPUS:84865786683
SN - 9781107019836
T3 - Proceedings of the International Astronomical Union
SP - 504
EP - 505
BT - Planetary Nebulae
PB - Cambridge University Press
ER -