view Abstract Citations (61) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Oxygen isotopic abundances in evolved stars. II. Eight MS and S stars. Harris, M. J. ; Lambert, D. L. ; Smith, V. V. Abstract Oxygen isotope ratios have been measured in five MS stars, two S stars, and the slightly s-process-rich M giant 30 Her. Both the 16O/17O and 16O/18O ratios are found to be much larger than expected from stellar evolution theories. Both 16O/17O and 16O/18O are found to correlate well with the abundance of 12C and with the degree of neutron exposure necessary to explain the s-process element abundances. These correlations cannot be explained by current theoretical models of AGB stars, nor by simple modifications of these models. Explosive nucleosynthesis in the envelope at extremely high temperatures during the helium core flash is tentatively proposed to explain them. Publication: The Astrophysical Journal Pub Date: December 1985 DOI: 10.1086/163707 Bibcode: 1985ApJ...299..375H Keywords: Abundance; Late Stars; M Stars; Oxygen Isotopes; S Stars; Stellar Evolution; Asymptotic Giant Branch Stars; Nuclear Fusion; Stellar Cores; Stellar Envelopes; Stellar Temperature; Astrophysics full text sources ADS | data products SIMBAD (10) Related Materials (3) Part 1: 1985ApJ...292..620H Part 3: 1987ApJ...316..294H Part 4: 1988ApJ...325..768H