Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: GG Tau: the fifth element   We aim at unveiling the observational imprint of physical mechanisms that
govern planetary formation in young, multiple systems. In particular, we
investigate the impact of tidal truncation on the inner circumstellar disks. We
observed the emblematic system GG Tau at high-angular resolution: a
hierarchical quadruple system composed of low-mass T Tauri binary stars
surrounded by a well-studied, massive circumbinary disk in Keplerian rotation.
We used the near-IR 4-telescope combiner PIONIER on the VLTI and
sparse-aperture-masking techniques on VLT/NaCo to probe this proto-planetary
system at sub-AU scales. We report the discovery of a significant closure-phase
signal in H and Ks bands that can be reproduced with an additional low-mass
companion orbiting GG Tau Ab, at a (projected) separation rho = 31.7 +/- 0.2mas
(4.4 au) and PA = 219.6 +/- 0.3deg. This finding offers a simple explanation
for several key questions in this system, including the missing-stellar-mass
problem and the asymmetry of continuum emission from the inner dust disks
observed at millimeter wavelengths. Composed of now five co-eval stars with
0.02 <= Mstar <= 0.7 Msun, the quintuple system GG Tau has become an ideal test
case to constrain stellar evolution models at young ages (few 10^6yr).

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The categories of this paper are: bayes-an
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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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: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org