International Symposium on Nuclei in the Cosmos XVIII (NIC XVIII)

Session

Stellar Abundances II – Presolar Grains

17 Jun 2025, 10:45

Girona

112. Presolar Grains as Probes of Type II Supernova Nucleosynthesis

Nan Liu (Boston University)

17/06/2025, 10:45

Contributed Poster

Presolar grains, submicron- to micron-sized meteoritic particles, originate from stellar winds and the ejecta of stellar explosions, providing direct samples of stellar material. Among these, silicon carbide (SiC) grains are particularly well-studied. Multielement isotope analyses of presolar SiC grains have firmly linked their origins to asymptotic giant branch (AGB) stars and core-collapse...

111. Correlated heavy isotope signatures in presolar SiC

Prof. Andrew Davis (University of Chicago)

17/06/2025, 11:15

Contributed Talk

The isotopic compositions of Zr, Mo, Ru, and Ba in presolar SiC have much to tell us about nucleosynthesis in stars, particularly asymptotic giant branch (AGB) stars, the likely sources of mainstream as well as types Y and Z presolar SiC grains. We highlight here two examples from recent simultaneous measurements on multiple elements in single presolar grains. (1) From their Mo and Ru isotopic...

351. Effects of Metallicity on Graphite, TiC, and SiC Condensation in Carbon Stars

Gabrielle Adams (Washington University in St. Louis)

17/06/2025, 11:30

205. Origin of Rare Isotopes in Presolar Grains as the Probe of Neutrino Mass Hierarchy and Supernova Nucleosynthesis

Dr Yudong Luo (Peking University)

17/06/2025, 11:45

Contributed Talk

Here we present our study on isotopic ratios of several typical neutrino-process nuclides in core-collapse supernova. We find that the measurement of isotopic ratios like 11B/10B with 138La/139La or 6Li/7Li can constrain neutrino mass hierarchy, providing new probes for understanding CCSN nucleosynthesis. Additionally, we show that the correlation between 138La/139La and 50Ti/48Ti in...

230. The Impact of Extra Mixing in Low-Mass Stars on Presolar Grain Abundance Predictions

Contributed Talk

Current stellar nucleosynthesis models fail to reproduce the measured isotopic abundances in group 2 oxygen-rich presolar grains, which are characterized by large ${}^{18}$O depletions compared to solar. It is proposed that cool bottom processing in low-mass AGB stars is responsible for the observed isotopic abundances. In this study, cool-bottom processing is modeled during the RGB and the...