Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: K2-31b, a grazing transiting hot Jupiter on an 1.26-day orbit around a
  bright G7V star   We report the discovery of K2-31b, the first confirmed transiting hot Jupiter
detected by the K2 space mission. We combined K2 photometry with FastCam lucky
imaging and FIES and HARPS high-resolution spectroscopy to confirm the
planetary nature of the transiting object and derived the system parameters.
K2-31b is a 1.8-Jupiter-mass planet on an 1.26-day-orbit around a G7\,V star
($M_\star=0.91$~\Msun, $R_\star=0.78$~\Rsun). The planetary radius is poorly
constrained (0.7$<$$R_\mathrm{p}$$<$1.4~\Rjup), owing to the grazing transit
and the low sampling rate of the K2 photometry.

2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin