Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The large amplitude outburst of the young star HBC 722 in NGC 7000/IC
  5070, a new FU Orionis candidate   We report the discovery of a large amplitude outburst from the young star HBC
722 (LkHA 188 G4) located in the region of NGC 7000/IC 5070. On the basis of
photometric and spectroscopic observations, we argue that this outburst is of
the FU Orionis type. We gathered photometric and spectroscopic observations of
the object both in the pre-outburst state and during a phase of increase in its
brightness. The photometric BVRI data (Johnson-Cousins system) that we present
were collected from April 2009 to September 2010. To facilitate transformation
from instrumental measurements to the standard system, fifteen comparison stars
in the field of HBC 722 were calibrated in the BVRI bands. Optical spectra of
HBC 722 were obtained with the 1.3-m telescope of Skinakas Observatory (Crete,
Greece) and the 0.6-m telescope of Schiaparelli Observatory in Varese (Italy).
The pre-outburst photometric and spectroscopic observations of HBC 722 show
both low amplitude photometric variations and an emission-line spectrum typical
of T Tau stars. The observed outburst started before May 2010 and reached its
maximum brightness in September 2010, with a recorded Delta V~4.7 mag.
amplitude. Simultaneously with the increase in brightness the color indices
changed significantly and the star became appreciably bluer. The light curve of
HBC 722 during the period of rise in brightness is similar to the light curves
of the classical FUors - FU Ori and V1057 Cyg. The spectral observations during
the time of increase in brightness showed significant changes in both the
profiles and intensity of the spectral lines. Only H alpha remained in
emission, while the H beta, Na I 5890/5896, Mg I triplet 5174, and Ba II
5854/6497 lines were in strong absorption.

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The categories of this paper are: comp-gas
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
16
The categories of this paper are: stat
1
The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex