Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gaps in the HD169142 protoplanetary disk revealed by polarimetric
  imaging: Signs of ongoing planet formation?   We present H-band VLT/NACO polarized light images of the Herbig Ae/Be star
HD169142 probing its protoplanetary disk as close as ~0.1" to the star. Our
images trace the face-on disk out to ~1.7" (~250 AU) and reveal distinct
sub-structures for the first time: 1) the inner disk (<20 AU) appears to be
depleted in scattering dust grains; 2) an unresolved disk rim is imaged at ~25
AU; 3) an annular gap extends from ~40 - 70 AU; 4) local brightness asymmetries
are found on opposite sides of the annular gap. We discuss different
explanations for the observed morphology among which ongoing planet formation
is a tempting - but yet to be proven - one. Outside of ~85 AU the surface
brightness drops off roughly r^{-3.3}, but describing the disk regions between
85-120 AU / 120-250 AU separately with power-laws r^{-2.6} / r^{-3.9} provides
a better fit hinting towards another discontinuity in the disk surface. The
flux ratio between the disk integrated polarized light and the central star is
~4.1 * 10^{-3}. Finally, combining our results with those from the literature,
~40% of the scattered light in the H-band appears to be polarized. Our results
emphasize that HD169142 is an interesting system for future planet formation or
disk evolution studies.

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The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
1
The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas