Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of Eclipsing Binary and Multiple Systems in OB Associations IV:
  Cas OB6 Member DN Cas   An early-type, massive, short-period ($P_{\rm orb}=2^{\rm d}.310951$)
eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and
photometric data. The masses and radii of the components have been obtained as
$M_1=19.04\pm0.07 M_\odot$, $M_2=13.73\pm 0.05M_\odot$ and $R_1=7.22\pm0.06
R_\odot$, $R_2=5.79\pm0.06R_\odot$, respectively. Both components present
synchronous rotation ($V_{\rm rot1}=160\,$km s$^{-1}$, $V_{\rm rot2}=130\,$km
s$^{-1}$) with their orbit. Orbital period analysis yielded a physically bound
additional component in the system with a minimum mass of $M_3=0.88 M_\odot$
orbiting in an eccentric orbit ($e=0.37\pm0.2$) with an orbital period of
$P_{12}=42\pm9$ yrs. High precision absolute parameters of the system allowed
us to derive a distance to DN Cas as 1.7$\pm$0.2 kpc which locates the system
within the borders of the Cas OB6 association (d=1.8 kpc; Mel'nik & Dambis,
2009). The space velocities and the age of DN Cas are in agreement with those
of Cas OB6. The age of DN Cas ($\tau=$3-5 Myr) is found to be 1-2 Myr older
than the embedded clusters (IC 1795, IC 1805 and IC 1848) in the Cas OB6
association, which implies a sequential star formation in the association.

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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg