Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Too little radiation pressure on dust in the winds of oxygen-rich AGB
  stars   New dynamical models for dust-driven winds of oxygen-rich AGB stars are
presented which include frequency-dependent Monte Carlo radiative transfer by
means of a sparse opacity distribution technique and a time-dependent treatment
of the nucleation, growth and evaporation of inhomogeneous dust grains composed
of a mixture of Mg2SiO4, SiO2, Al2O3, TiO2, and solid Fe. The
frequency-dependent treatment of radiative transfer reveals that the gas is
cold close to the star (700-900 K at 1.5-2 R*) which facilitates the nucleation
process. The dust temperatures are strongly material-dependent, with
differences as large as 1000 K for different pure materials, which has an
important influence on the dust formation sequence. Two dust layers are formed
in the dynamical models: almost pure glassy Al2O3 close to the star (r > 1.5
R*) and the more opaque Fe-poor Mg-Fe-silicates further out. Solid Fe or
Fe-rich silicates are found to be the only condensates that can efficiently
absorb the stellar light in the near IR. Consequently, they play a crucial role
for the wind driving mechanism and act as thermostat. Only small amounts of Fe
can be incorporated into the grains, because otherwise the grains get too hot.
Thus, the models reveal almost no mass loss, and no dust shells.

14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con