Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic activity on AB Doradus: Temporal evolution of starspots and
  differential rotation from 1988 to 1994   Surface brightness maps for the young K0 dwarf AB Doradus are reconstructed
from archival data sets for epochs spanning 1988 to 1994. By using the
signal-to-noise enhancement technique of Least-Squares Deconvolution, our
results show a greatly increased resolution of spot features than obtained in
previously published surface brightness reconstructions. These images show that
for the exception of epoch 1988.96, the starspot distributions are dominated by
a long-lived polar cap, and short-lived low to high latitude features. The
fragmented polar cap at epoch 1988.96 could indicate a change in the nature of
the dynamo in the star. For the first time we measure differential rotation for
epochs with sufficient phase coverage (1992.05, 1993.89, 1994.87). These
measurements show variations on a timescale of at least one year, with the
strongest surface differential rotation ever measured for AB Dor occurring in
1994.86. In conjunction with previous investigations, our results represent the
first long-term analysis of the temporal evolution of differential rotation on
active stars.

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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
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The categories of this paper are: stat
37
The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics