On the surface composition of thermally pulsing stars of high luminosity and on the contribution of such stars to the element enrichment of the interstellar medium

Abstract

view Abstract Citations (443) References (61) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the surface composition of thermally pulsing stars of high luminosity and on the contribution of such stars to the element enrichment of the interstellar medium. Iben, I., Jr. ; Truran, J. W. Abstract Enhancements of He-3, He-4, C-12, C-13, N-14, Ne-22, and s-process elements at the surfaces of stars of different initial mass that eventually experience thermal pulses are investigated. The results obtained show that: (1) significant enhancement of s-process elements does not occur for luminosities less than a bolometric magnitude of about -6; (2) for stars of a given initial composition, the surface abundance of C-12 exceeds that of O-16 at roughly the same surface temperature, independent of mass; (3) stars initially less massive than about 1.5 solar masses do not become carbon stars as a consequence of thermal pulses; (4) stars initially less massive than about 2.5 solar masses do not achieve convective-shell temperatures sufficiently high for the production of s-process elements before losing all of their envelope mass by quiet mass loss or ejection of planetary nebulae; (5) surface enhancements of s-process elements in stars initially more massive than about 3 solar masses ultimately reach values between 4 and 20, with the maximum enhancement occurring in stars of initial mass near 5 solar masses; and (6) stars of initial mass between 3 and 8 solar masses are the major source of s-process elements in the Galaxy and a significant source of C-12. Publication: The Astrophysical Journal Pub Date: March 1978 DOI: 10.1086/155986 Bibcode: 1978ApJ...220..980I Keywords: Abundance; Interstellar Matter; Late Stars; Nuclear Fusion; Stellar Evolution; Stellar Models; Enrichment; Hertzsprung-Russell Diagram; Pulses; Stellar Luminosity; Stellar Mass; Tables (Data); Astrophysics; Chemical Composition:Stellar Surfaces; Element Abundances:Interstellar Matter; Nucleosynthesis:Stellar Interiors; Pulsations:Stellar Models full text sources ADS |