Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A TGAS/Gaia DR1 parallactic distance to the sigma Orionis cluster   With the new Tycho-Gaia Astrometric Solution, I derive a new parallactic
distance to the young sigma Orionis open cluster, which is a cornerstone region
for studying the formation and evolution of stars and substellar objects from
tens of solar masses to a few Jupiter masses. I started with the list of the 46
brightest cluster stars of Caballero (2007). After identifying the 24 TGAS
stars in the 30 arcmin-radius survey area and accounting for 11 FGKM-type
dwarfs and giants in the fore- and background, I got a list of 13 cluster
members and candidates with new parallaxes. Of them, I discarded five cluster
member candidates with questionable features of youth and/or discordant
parallaxes and proper motions, including a distant Herbig Ae/Be star, and
proceeded with the remaining eight stars. The sigma Orionis mean heliocentric
distance is d =360^{+44}_{-35} pc, which is consistent with a contemporaneous
interferometric determination that concludes a two-decade dispute on the
cluster distance. As a by-product, the re-classification of those five cluster
member candidates, now interlopers, shows a manifest deficit of cluster stars
between 1.2 and 2.1 Msol, which leaves the door open to new astrometric
membership analyses with the next Gaia data releases.

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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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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: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: physics