Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Uranus' aurorae past equinox   The aurorae of Uranus were recently detected in the far ultraviolet with the
Hubble Space Telescope (HST) providing a new, so far unique, means to remotely
study the asymmetric Uranian magnetosphere from Earth. We analyze here two new
HST Uranus campaigns executed in Sept. 2012 and Nov. 2014 with different
temporal coverage and under variable solar wind conditions numerically
predicted by three different MHD codes. Overall, HST images taken with the
Space Telescope Imaging Spectrograph reveal auroral emissions in three pairs of
successive images (one pair acquired in 2012 and two in 2014), hence six
additional auroral detections in total, including the most intense Uranian
aurorae ever seen with HST. The detected emissions occur close the expected
arrival of interplanetary shocks. They appear as extended spots at southern
latitudes, rotating with the planet. They radiate 5-24 kR and 1.3-8.8 GW of
ultraviolet emission from H$_2$, last for tens of minutes and vary on
timescales down to a few seconds. Fitting the 2014 observations with model
auroral ovals constrains the longitude of the southern (northern) magnetic pole
to 104+\-26{\deg} (284-\-26{\deg}) in the Uranian Longitude System. We suggest
that the Uranian near-equinoctial aurorae are pulsed cusp emissions possibly
triggered by large-scale magnetospheric compressions.

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The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th