Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of Two Rare Rigidly-Rotating Magnetosphere Stars in the APOGEE
  Survey   The Apache Point Observatory Galactic Evolution Experiment (APOGEE) - one of
the Sloan Digital Sky Survey III programs -- is using near-infrared spectra of
$\sim 100,000$ red giant branch star candidates to study the structure of the
Milky Way. In the course of the survey, APOGEE also acquires spectra of hot
field stars to serve as telluric calibrators for the primary science targets.
We report the serendipitous discovery of two rare, fast-rotating B stars of the
$\sigma$ Ori E type among those blue field stars observed during the first year
of APOGEE operations. Both of the discovered stars display the spectroscopic
signatures of the rigidly rotating magnetospheres (RRM) common to this class of
highly-magnetized ($B \sim 10$ kiloGauss) stars, increasing the number of known
RRM stars by $\sim 10 \%$. One (HD 345439) is a main-sequence B star with
unusually strong He absorption (similar to $\sigma$ Ori E), while the other (HD
23478) fits a "He-normal" B3IV classification. We combine the APOGEE discovery
spectra with other optical and near-infrared spectra of these two stars, and of
$\sigma$ Ori E itself, to show how near-infrared spectroscopy can be a uniquely
powerful tool for discovering more of these rare objects, which may show
little/no RRM signatures in their optical spectra. We discuss the potential for
further discovery of $\sigma$ Ori E type stars, as well as the implications of
our discoveries for the population of these objects and insights into their
origin and evolution.

36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci