Abstract
Abstract Molybdenum isotopes measured in most individual presolar silicon carbide grains are dominated by s-process contributions from the helium intershells of asymptotic giant branch (AGB) stars. The much smaller isotopic variations in molybdenum in meteorites and their components are largely controlled by s-process enrichments or depletions relative to terrestrial composition but lie along two parallel s-process mixing lines separated by what has been suggested to be an r-process contribution. The two mixing lines are populated by carbonaceous-chondrite- and noncarbonaceous-chondrite-related meteorites (CC and NC groups, respectively). We have compared molybdenum isotopic data for presolar grains with those from meteorites and renormalized the meteorite data in a way that is consistent with s-, r-, and p-process contributions observed in presolar SiC grains. The results indicate that (1) there seems to be a fixed ratio between p- and r-process contributions in all data, (2) the dichotomy in molybdenum isotopes between the CC and NC groups can be explained by variations in the isotope makeup of the s-process contribution to the meteoritic samples, (3) this variability is similar to the variations in s-process molybdenum from different AGB stars deduced from presolar grain analyses, and (4) the larger range of isotopic compositions found in refractory inclusions is also consistent with s-process isotope variability.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
