Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The expanding dusty bipolar nebula around the nova V1280 Sco   V1280 Sco is one of the slowest dust-forming nova ever historically observed.
We performed multi-epoch high-spatial resolution observations of the
circumstellar dusty environment of V1280 Sco to investigate the level of
asymmetry of the ejecta We observed V1280 Sco in 2009, 2010 and 2011 using
unprecedented high angular resolution techniques. We used the NACO/VLT adaptive
optics system in the J, H and K bands, together with contemporaneous VISIR/VLT
mid-IR imaging that resolved the dust envelope of V1280 Sco, and SINFONI/VLT
observations secured in 2011. We report the discovery of a dusty
hourglass-shaped bipolar nebula. The apparent size of the nebula increased from
0.30" x 0.17" in July 2009 to 0.64" x 0.42" in July 2011. The aspect ratio
suggests that the source is seen at high inclination. The central source shines
efficiently in the K band and represents more than 56+/-5% of the total flux in
2009, and 87+/-6% in 2011. A mean expansion rate of 0.39+/-0.03 mas per day is
inferred from the VISIR observations in the direction of the major axis, which
represents a projected upper limit. Assuming that the dust shell expands in
that direction as fast as the low-excitation slow ejecta detected in
spectroscopy, this yields a lower limit distance to V1280 Sco of 1kpc; however,
the systematic errors remain large due to the complex shape and velocity field
of the dusty ejecta. The dust seems to reside essentially in the polar caps and
no infrared flux is detected in the equatorial regions in the latest dataset.
This may imply that the mass-loss was dominantly polar.

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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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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: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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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: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ