Abundance ratio /sup 18/O//sup 17/O in hot CNO nucleosynthesis

Journal Article · Fri Jul 01 04:00:00 EDT 1977 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/155348· OSTI ID:7319434

Norgaard, H

Hot CNO burning is investigated with special emphasis on the ratio of mass 18 to mass 17 nuclei. First, claculations for constant temperature, T, and density, rho, are discussed. For T/sub 8/=1 and 2 and rho=100 g cm/sup -3/, the conditions which Cowan and Rose suggested should yield high (>1) values of /sup 18/O//sup 17/O, it is found that the production of mass 18 nuclei is particularly sensitive to the rates of the reactions /sup 18/F(p, ..cap alpha..)/sup 15/O and /sup 18/F(p, ..gamma..)/sup 19/Ne, which are, however, not available from experiment. Using the estimates for these rates proposed by Wagoner, one obtains values of /sup 18/O//sup 17/O which are several orders of magnitude smaller than those found by Cowan and Rose, who neglected these reactions. For 4PmsT/sub 8/< or =8 and 10/sup 2/< or =rho< or =10/sup 4/ g cm/sup -3/, which may be characteristic of conditions in novae, supermassive stars, and outer zones of supernovae, substantial simultaneous overproduction (relative to the solar system value) of mass 17 and mass 18 concomitant overproduction of mass 15 nuclei greatly exceeds that of both mass 17 and mass 18 nuclei. In addition, it is found that the influence of hydrodynamic freeze-out tends to decrease that hot CNO burning probably is unable to account for high (>1) ratios of /sup 18/O//sup 17/O. Finally, the need for improved rates of several reactions governing the production of mass 17 and mass 18 nuclei is emphasized.

• Research Organization: Nordita, Copenhagen
• OSTI ID: 7319434
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 215:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics &amp; Cosmology-- Stars &amp; Quasi-Stellar
Radio &amp; X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GIANT STARS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
NOVAE
NUCLEAR REACTIONS
NUCLEI
NUCLEOSYNTHESIS
OXYGEN 17
OXYGEN 18
OXYGEN ISOTOPES
STABLE ISOTOPES
STARS
SUPERGIANT STARS