Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wind properties of Wolf-Rayet stars at low metallicity: Sk41 (SMC)   The stellar properties of Sk41 (AB4, WN5h), the only known single Wolf-Rayet
star in the SMC, are derived from ultraviolet (IUE), optical (AAT) and near-IR
(NTT) spectroscopy. Contrary to expectations, the stellar properties of Sk41
are typical of equivalent WN stars in the Galaxy and LMC, with T=42kK,
log(L/Lo)=5.7, v_inf=1300 km/s, Mdot/sqrt(f)=3x10^-5 Mo/yr and H/He=2 by
number, where f is the volume filling factor. The stellar luminosity of Sk41 is
50% below the minimum value predicted by single star evolutionary models at the
metallicity of the SMC.
  Emission line luminosities of HeII 4686A and CIV 5801-12A in SMC WR stars are
not systematically lower than their Galactic and LMC counterparts. From 43
late-type and 59 early-type WN stars, log L(HeII)=36.0 erg/s and 35.8 erg/s
respectively, while log L(CIV)=36.5 erg/s from 25 early-type WC stars. This new
calibration has application in deriving WR populations in young starburst
galaxies.
  Synthetic WN models are calculated with identical parameters except that
metal abundances are varied. Following the Smith et al. WN classification
scheme, CNO equilibrium models reveal that earlier spectral types are predicted
at lower metallicity, i.e. WN3--4 at 0.04 Z(solar) versus WN6 at 1.0 Z(solar).
This provides an explanation for the trend towards earlier WN spectral types at
low metallicity.

24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin