Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HST Spectroscopy of the Hottest White Dwarfs   Spectral analysis needs the observation of lines of successive ionization
stages in order to evaluate the ionization equilibrium (of a particular
species) which is a sensitive indicator for the effective temperature. Since
stars with effective temperatures as high as 100000 K have their flux maximum
in the extreme ultraviolet (EUV) wavelength range and due to the high degree of
ionization, most of the metal lines are found in the ultraviolet (UV) range.
Thus, high-S/N and high-resolution UV spectra are a pre-requisite for a precise
analysis. Consequently, we employed the Faint Object Spectrograph (FOS), the
Goddard High Resolution Spectrograph (GHRS), and the Space Telescope Imaging
Spectrograph (STIS) aboard the Hubble Space Telescope (HST) in order to obtain
suitable data. We present state-of-the-art analyses of the hottest (pre-) white
dwarfs by means of NLTE model atmospheres which include the metal-line
blanketing of all elements from hydrogen to nickel.

25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org