Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct Imaging of Fine Structures in Giant Planet Forming Regions of the
  Protoplanetary Disk around AB Aurigae   We report high-resolution 1.6 $\micron$ polarized intensity ($PI$) images of
the circumstellar disk around the Herbig Ae star AB Aur at a radial distance of
22 AU ($0."15$) up to 554 AU (3.$"$85), which have been obtained by the
high-contrast instrument HiCIAO with the dual-beam polarimetry. We revealed
complicated and asymmetrical structures in the inner part ($\lesssim$140 AU) of
the disk, while confirming the previously reported outer ($r$ $\gtrsim$200 AU)
spiral structure. We have imaged a double ring structure at $\sim$40 and
$\sim$100 AU and a ring-like gap between the two. We found a significant
discrepancy of inclination angles between two rings, which may indicate that
the disk of AB Aur is warped. Furthermore, we found seven dips (the typical
size is $\sim$45 AU or less) within two rings as well as three prominent $PI$
peaks at $\sim$40 AU. The observed structures, including a bumpy double ring, a
ring-like gap, and a warped disk in the innermost regions, provide essential
information for understanding the formation mechanism of recently detected
wide-orbit ($r$ $>$20 AU) planets.

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The categories of this paper are: econ
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
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The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg