Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Eclipses by a Circumstellar Dust Feature in the Pre-Main Sequence Star
  KH15D   Photometry and spectroscopy of the unique pre-main sequence eclipsing object
KH15D in the young cluster NGC 2264 are presented. The orbital period is 48.34
days and both the length (~16 d) and depth (~3 mag) of the eclipse have
increased with time. A brightening near the time of central eclipse is
confirmed in the recent data but at a much smaller amplitude than was
originally seen. Spectra taken when the star is bright show that the primary is
a weak T Tauri star of spectral type K7. During eclipse there is no detectable
change in spectral type or reddening, indicating that the obscuration is caused
by rather large dust grains and/or macroscopic objects. Evidently the star is
eclipsed by an extended feature in its circumstellar disk orbiting with a
semi-major axis of ~0.2 AU. Continued photometric monitoring should allow us to
probe the disk structure with a spatial resolution of ~3 x 10^6 km or better.

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The categories of this paper are: hep-lat
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
3
The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: econ