Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Gemini NICI Planet-Finding Campaign: The Orbit of the Young
  Exoplanet beta Pictoris b   We present new astrometry for the young (12--21 Myr) exoplanet beta Pictoris
b taken with the Gemini/NICI and Magellan/MagAO instruments between 2009 and
2012. The high dynamic range of our observations allows us to measure the
relative position of beta Pic b with respect to its primary star with greater
accuracy than previous observations. Based on a Markov Chain Monte Carlo
analysis, we find the planet has an orbital semi-major axis of 9.1 (+5.3, -0.5)
AU and orbital eccentricity <0.15 at 68% confidence (with 95% confidence
intervals of 8.2--48 AU and 0.00--0.82 for semi-major axis and eccentricity,
respectively, due to a long narrow degenerate tail between the two). We find
that the planet has reached its maximum projected elongation, enabling higher
precision determination of the orbital parameters than previously possible, and
that the planet's projected separation is currently decreasing. With
unsaturated data of the entire beta Pic system (primary star, planet, and disk)
obtained thanks to NICI's semi-transparent focal plane mask, we are able to
tightly constrain the relative orientation of the circumstellar components. We
find the orbital plane of the planet lies between the inner and outer disks:
the position angle (PA) of nodes for the planet's orbit (211.8 +/- 0.3 degrees)
is 7.4 sigma greater than the PA of the spine of the outer disk and 3.2 sigma
less than the warped inner disk PA, indicating the disk is not collisionally
relaxed. Finally, for the first time we are able to dynamically constrain the
mass of the primary star beta Pic to 1.76 (+0.18, -0.17) solar masses.

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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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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: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex