Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral analysis of four multi mode pulsating sdB stars   Four members of the new class of pulsating sdB stars are analysed from Keck
HIRES spectra using NLTE and LTE model atmospheres. Atmospheric parameters
(Teff, log g, log(He/H)), metal abundances and rotational velocities are
determined. Balmer line fitting is found to be consistent with the helium
ionization equilibrium for PG1605+072 but not so for PG1219+534 indicating that
systematic errors in the model atmosphere analysis of the latter have been
underestimated previously. All stars are found to be helium deficient probably
due to diffusion. The metals are also depleted with the notable exception of
iron which is solar to within error limits in all four stars, confirming
predictions from diffusion calculations of Charpinet et al. (1997). While three
of them are slow rotator's (vsini < 10km/s), PG1605+072 displays considerable
rotation (vsini = 39km/s, P<8.7h) and is predicted to evolve into an unusually
fast rotating white dwarf. This nicely confirms a prediction by Kawaler (1999)
who deduced a rotation velocity of 130km/s from the power spectrum of the
pulsations which implies a low inclination angle of the rotation axis.

20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc