Open AccessInvestigation of the single neutron exposure model for the s ‐process: the primary nature of the neutron source
Author(s) -
Ma Kun,
Cui Wenyuan,
Zhang Bo
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11403.x
Subject(s) - physics , nucleosynthesis , r process , s process , neutron star , neutron , neutron source , nuclear physics , astrophysics , neutron cross section , neutron capture , stellar nucleosynthesis , nuclear reaction , neutron temperature
The primary nature of the 13 C neutron source is very significant for the studies of the s ‐process nucleosynthesis. In this paper we present an attempt to fit the element abundances observed in 16 s ‐rich stars using parametric model of the single neutron exposure. The calculated results indicate that almost all s ‐elements were made in a single neutron exposure for nine sample stars. Although a large spread of neutron exposure is obtained, the maximum value of the neutron exposure will reach about 7.0 mbarn −1 , which is close to the theoretical predictions by the asymptotic giant branch (AGB) model. The calculated result is a significant evidence for the primary nature of the neutron source. Combining the result obtained in this work and the neutron exposure–initial mass relations, a large spread of neutron exposure can be explained by the different initial stellar mass and their time evolution. The possibility that the rotationally induced mixing process can lead to a spread of the neutron exposure in AGB stars is also existent.