Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: V2494 Cyg: A unique FU Ori type object in the Cygnus OB7 complex   A photometric and spectral study of the variable star V2494 Cyg in the L 1003
dark cloud is presented. The brightness of the star, formerly known as HH 381
IRS, increased by 2.5 mag in R (probably in the 1980s) and since then has
remained nearly constant. Since the brightness increase, V2494 Cyg has
illuminated a bipolar cometary nebula. The stellar spectrum has several
features typical of the FU Ori type, plus it exhibits very strong Halpha and
forbidden emission lines with high-velocity components. These emission lines
originate in the HH jet near the star. The kinematic age of the jet is
consistent with it forming at the time of the outburst leading to the
luminosity increase. V2494 Cyg also produces a rather extended outflow; it is
the first known FUor with both an observed outburst and a parsec-sized HH flow.
The nebula, illuminated by V2494 Cyg, possesses similar morphological and
spectral characteristics to Hubble's Variable Nebula (R Monocerotis/NGC 2261).

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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg