Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hot Stars: Old-Fashioned or Trendy?   Spectroscopic analyses with the intention of the interpretation of the
UV-spectra of the brightest stars as individuals - supernovae - or as
components of star-forming regions - massive O stars - provide a powerful tool
with great astrophysical potential for the determination of extragalactic
distances and of the chemical composition of star-forming galaxies even at high
redshifts.
  The perspectives of already initiated work with the new generation of tools
for quantitative UV-spectroscopy of Hot Stars that have been developed during
the last two decades are presented and the status of the continuing effort to
construct corresponding models for Hot Star atmospheres is reviewed.
  Because the physics of the atmospheres of Hot Stars are strongly affected by
velocity expansion dominating the spectra at all wavelength ranges,
hydrodynamic model atmospheres for O-type stars and explosion models for
Supernovae of Type Ia are necessary as basis for the synthesis and analysis of
the spectra. It is shown that stellar parameters, abundances and stellar wind
properties can be determined by the methods of spectral diagnostics already
developed. Additionally, it will be demonstrated that models and synthetic
spectra of Type Ia Supernovae of required quality are already available that
make it possible to tackle the question of whether Supernovae Ia are standard
candles in a cosmological sense and the SN-luminosity distances thus indicate
accelerated expansion of the universe.

5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
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
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph