s-Process Implications from Osmium Isotope Anomalies in Chondrites

Details s-Process Implications from Osmium Isotope Anomalies in Chondrites s-Process Implications from Osmium Isotope Anomalies in Chondrites

Jul 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007apj...664l..59h&link_type=abstract

The Astrophysical Journal, Volume 664, Issue 1, pp. L59-L62.

Astronomy and Astrophysics

Astronomy

2

Nuclear Reactions, Nucleosynthesis, Abundances, Solar System: General

Scientific paper

Correlated isotopic anomalies in osmium (186Os, 188Os, 190Os, measured with respect to 189Os) extracted from primitive carbonaceous chondrites tightly constrain the σn(190Os)/σn(188Os) ratio to be 0.859+/-0.042 (+/-5%). A recent measurement of the Maxwellian-averaged neutron-capture cross sections (MACSs) for 186,187,188Os lowered the σn(188Os) by 27% but did not measure σn(190Os). From the σn(190Os)/σn(188Os) ratio, we infer σn(190Os)=249+/-18 mbarns for internal consistency with the new MACSs for the other Os isotopes. This approach is applicable to other isotopic anomalies in r-process/s-process ratios derived from meteorites for nuclei that do not have branching points between them. Branching at 185W and 186Re makes the 186Os/188Os ratio a neutron dosimeter for the s-process that, with the new cross sections, yields an average neutron density, nn~3×108 cm-3. This low neutron density is consistent with previous results from Sr, Zr, Mo, and Ba isotopes that indicated a minor contribution from the 22Ne(α, n)25Mg neutron source relative to the 13C(α, n)16O neutron source.

Affiliated with

Also associated with

No associations

Rating

s-Process Implications from Osmium Isotope Anomalies in Chondrites 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 s-Process Implications from Osmium Isotope Anomalies in Chondrites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and s-Process Implications from Osmium Isotope Anomalies in Chondrites will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1031004