Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Recent Progress in the Understanding of the r-Process   A brief overview of the r-process is given with an emphasis on the
observational implications for this process. The conditions required for the
major production of the heavy r-process elements (r-elements) with mass numbers
A >130 are discussed based on a generic astrophysical model where matter
adiabatically expands from a hot and dense initial state. Nucleosynthesis in
the neutrino-driven winds from nascent neutron stars is discussed as a specific
example. Such winds readily produce the elements from Sr to Ag with A ~ 88 to
110 through charged-particle reactions in the alpha-process but appear
incapable of making the heavy r-elements. Observations of elemental abundances
in metal-poor stars have provided many valuable insights into the r-process.
They have demonstrated that the production of the heavy r-elements must be
associated with massive stars evolving on short timescales, provided evidence
strongly favoring core-collapse supernovae over neutron star mergers as the
major source for these elements, and shown that this source cannot produce any
significant amount of the low-A elements from Na to Ge including Fe. A
self-consistent astrophysical model of the r-process remains to be developed,
and it appears well worthwhile to carry out more comprehensive studies on the
evolution and explosion of the massive stars of ~ 8 to 11 M_sun that undergo
O-Ne-Mg core collapse and produce a very insignificant amount of the low-A
elements.

32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys