Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Morphology of IRC +10420's Circumstellar Ejecta   Images of the circumstellar ejecta associated with the post-red supergiant
IRC +10420 show a complex ejecta with visual evidence for episodic mass loss.
In this paper we describe the transverse motions of numerous knots, arcs and
condensations in the inner ejecta measured from second epoch {\it HST/WFPC2}
images. When combined with the radial motions for several of the features, the
total space motion and direction of the outflows show that they were ejected at
different times, in different directions, and presumably from separate regions
on the surface of the star. These discrete structures in the ejecta are
kinematically distinct from the general expansion of the nebula and their
motions are dominated by their transverse velocities. They are apparently all
moving within a few degrees of the plane of the sky. We are thus viewing IRC
+10420 nearly pole-on and looking nearly directly down onto its equatorial
plane. We also discuss the role of surface activity and magnetic fields on IRC
+10420's recent mass loss history.

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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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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: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: cond-mat