Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chemical Evolution of the Galaxy: the G-dwarf problem and radioactive
  chronology revisited taking account of the Thick Disk   Thin and Thick disk metallicities overlap, but alpha(Fe) relations differ;
there is also a hiatus in time before the first thin-disk stars, with a minimum
metallicity [Fe/H] = -0.6. Thus there are two `G-dwarf' problems. We fit
metallicity distribution functions (MDFs) for the two disks derived by Wyse &
Gilmore (1995) with analytical models (for O and Mg). The Thick disk fits a
simple inflow model with effective yield and final [Mg/H] about the same as for
the Thin Disk, excluding continuous mass loss from the former as a source of
prompt initial enrichment (PIE) for the latter. The Thin disk has a narrow MDF
fitted (rather poorly) with a closed model having PIE from some other source,
or more elegantly with a slow infall model similar to the `two-inflow' scenario
of Matteucci et al., but with a PIE and a severe break in the age-metallicity
relation. Implications for radio-active cosmochronology are investigated.

20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess