Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigation of the single neutron exposure model for the s-process:
  the primary nature of the neutron source   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 9 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 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.

11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th