Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transient Mass-Loss Events in the PG 1159 Central Star of Longmore 4   A spectacular, transient mass-loss event in the hydrogen-deficient central
star of the planetary nebula Longmore 4 was discovered in 1992 by Werner et al.
During that event, the star temporarily changed from its normal PG 1159
spectrum to that of an emission-line [WCE] star. I have been monitoring the
spectrum of Lo 4 since 2003. Out of 31 spectra, two of them reveal mass-loss
outbursts similar to the one seen in 1992, showing that the phenomenon recurs.
I speculate on possible mechanisms for these unique outbursts, but emphasize
that we still have no fully convincing explanation.

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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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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: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: stat