Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NGC 7419: A young open cluster with a number of very young intermediate
  mass pre-MS stars   We present a photometric and spectroscopic study of the young open cluster
NGC 7419, which is know to host a large number of classical Be stars for
reasons not well understood. Based on CCD photometric observations of 327 stars
in UBV passbands, we estimated the cluster parameters as, reddening E(B-V) =
1.65 +/- 0.15 mag and distance = 2900 +/- 400 pc. The turn off age of the
cluster was estimated as 25 +/- 5 Myr using isochrone fits. UBV data of the
stars were combined with JHK data from 2MASS and were used to create the near
infrared (NIR) (J-H) vs (H-K) colour-colour diagram. A large fraction of stars
(42%) was found to have NIR excess and their location in the diagram was used
to identify them as intermediate mass pre-MS stars. The isochrone fits to
pre-MS stars in the optical colour-magnitude diagram showed that the turn-on
age of the cluster is 0.3 - 3 Myr. This indicates that there has been a recent
episode of star formation in the vicinity of the cluster. Slit-less spectra
were used to identify 27 stars which showed H-alpha in emission in the field of
the cluster, of which 6 are new identifications. All these stars were found to
show NIR excess and located closer to the region populated by Herbig Ae/Be
stars in the (J-H) vs (H-K) diagram. Slit spectra of 25 stars were obtained in
the region 3700A - 9000A. The spectral features were found to be very similar
to those of Herbig Be stars. Those stars were found to be more reddened than
the main sequence stars by 0.4 mag on an average. Thus the emission line stars
found in this cluster are more similar to the Herbig Be type stars where the
circumstellar material is the remnant of the accretion disk.

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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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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: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: econ