Presolar silicon carbide grains of types Y and Z: their strontium and barium isotopic compositions and stellar origins

· by · in

Nan Liu, Thomas Stephan, Sergio Cristallo, Diego Vescovi, Roberto Gallino, Larry R. Nittler, Conel M. O’ D. Alexander & Andrew M. Davis

The European Physical Journal A, Volume 58, Article number: 216
Published: 10 November 2022

LINK

“We report the Sr and Ba isotopic compositions of 18 presolar SiC grains of types Y (11) and Z (7), rare types commonly argued to have formed in lower-than-solar metallicity asymptotic giant branch (AGB) stars. We find that the Y and Z grains show higher 88Sr/87Sr and more variable 138Ba/136Ba ratios than mainstream (MS) grains. According to FRANEC Torino AGB models, the Si, Sr, and Ba isotopic compositions of our Y and Z grains can be consistently explained if the grains came from low-mass AGB stars with 0.15 Z⊙ ≤ Z < 1.00 Z⊙, in which the 13C neutron exposure for the slow neutron-capture process is greatly reduced with respect to that required by MS grains for a 1.0 Z⊙ AGB star. This scenario is in line with the previous finding based on Ti isotopes, but it fails to explain the indistinguishable Mo isotopic compositions of MS, Y, and Z grains.”

Related posts (automatically generated):

  1. Presolar Silicon Carbide Grains of Types Y and Z: Their Molybdenum Isotopic Compositions and Stellar OriginsOPEN ACCESS 
  2. Strontium and barium isotopes in presolar silicon carbide grains measured with CHILI—two types of X grains
  3. New Multielement Isotopic Compositions of Presolar SiC Grains: Implications for Their Stellar Origins
  4. Simultaneous iron and nickel isotopic analyses of presolar silicon carbide grains
  5. Correlated Strontium and Barium Isotopic Compositions of Acid-cleaned Single Mainstream Silicon Carbides from Murchison
  6. Isotopic Signatures of Supernova Nucleosynthesis in Presolar Silicon Carbide Grains of Type AB with Supersolar 14N/15N Ratios
  7. Correlated silicon and titanium isotopic compositions of presolar sic grains from the Murchison CM2 chondrite
  8. NanoSIMS Isotope Studies of Rare Types of Presolar Silicon Carbide Grains from the Murchison Meteorite: Implications for Supernova Models and the Role of 14C
  9. Iron and nickel isotope compositions of presolar silicon carbide grains from supernovae
  10. Sulfur in presolar silicon carbide grains from asymptotic giant branch stars
Tags: , , , , , ,