Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Nature of the Unique H$\alpha$-Emitting T Dwarf 2MASS
  J12373919+6526148   We explore and discount the hypothesis that the strong, continual
H$\alpha$-emitting T dwarf 2MASS J12373919+6526148 can be explained as a young,
low gravity, very low mass brown dwarf. The source is already known to have a
marginally-fainter absolute magnitude than similar T dwarfs with trigonometric
parallax measurements, and has a tangential velocity consistent with old disk
kinematics. Applying the technique of Burgasser, Burrows & Kirkpatrick on new
near infrared spectroscopy for this source, estimates of its {\teff}, $\log{g}$
and metallicity ([M/H]) are obtained. 2M 1237+6526 has a {\teff} $\approx$
800-850 K. If [M/H] is solar, $\log{g}$ is as high as $\sim$5.5 (cgs) and this
source is older than 10 Gyr. We find a more plausible scenario to be a modestly
subsolar metallicity ([M/H] = -0.2) and moderate $\log{g}$ $\sim$ 5.0, implying
an age older than 2 Gyr and a mass greater than 0.035 M$_{\sun}$. The
alternative explanation of the unique emission of this source, involving an
interacting, close, double degenerate system, should be investigated further.
Indeed, there is some evidence of a {\teff} $<$ 500 K companion to 2M 1237+6526
on the basis of a possible $Spitzer IRAC$ [3.6]--[4.5] color excess. This
excess may, however, be caused by a subsolar metallicity.

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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
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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: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga