Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Early Results from the Galactic O-Star Spectroscopic Survey: C III
  Emission Lines in Of Spectra   On the basis of an extensive new spectroscopic survey of Galactic O stars, we
introduce the Ofc category, which consists of normal spectra with C III
\lambda\lambda4647-4650-4652 emission lines of comparable intensity to those of
the Of defining lines N III \lambda\lambda4634-4640-4642. The former feature is
strongly peaked to spectral type O5, at all luminosity classes, but
preferentially in some associations or clusters and not others. The
relationships of this phenomenon to the selective C III \lambda5696 emission
throughout the normal Of domain, and to the peculiar, variable Of?p category,
for which strong C III \lambda\lambda4647-4650-4652 emission is a defining
characteristic, are discussed. Magnetic fields have recently been detected on
two members of the latter category. We also present two new extreme Of?p stars,
NGC 1624-2 and CPD -28^{\circ}2561, bringing the number known in the Galaxy to
five. Modeling of the behavior of these spectral features can be expected to
better define the physical parameters of both normal and peculiar objects, as
well as the atomic physics involved.

11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th