Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Models for extremely metal-poor halo stars   Two alternative scenarios concerning the origin and evolution of extremely
metal-poor halo stars are investigated. The first one assumes that the stars
have been completely metal-free initially and produced observed carbon and
nitrogen overabundances during the peculiar core helium flash typical for
low-mass Population-III stars. The second scenario assumes that the initial
composition resulted from a mixture of primordial material with ejecta from a
single primordial supernovae. Both scenarios are shown to have problems in
reproducing C, N, and O abundances simultaneously, and both disagree with
observed 12C/13C-ratios,though in different directions. We concentrate on the
most iron-poor, carbon-rich object of this class, HE0107-5240, and conclude
that the second scenario presently offers the more promising approach to
understand these objects, in particular because evolutionary tracks match
observations very well.

24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th