Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revealing companions to nearby stars with astrometric acceleration   A subset of 51 Hipparcos astrometric binaries among FG dwarfs within 67pc has
been surveyed with the NICI adaptive optics system at Gemini-S, directly
resolving for the first time 17 sub-arcsecond companions and 7 wider ones.
Using these data together with published speckle interferometry of 57 stars, we
compare the statistics of resolved astrometric companions with those of a
simulated binary population. The fraction of resolved companions is slightly
lower than expected from binary statistics. About 10% of astrometric companions
could be "dark" (white dwarfs and close pairs of late M-dwarfs). To our
surprise, several binaries are found with companions too wide to explain the
acceleration. Re-analysis of selected intermediate astrometric data shows that
some acceleration solutions in the original Hipparcos catalog are spurious.

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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an