Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters
  and a planet in the transition region between ice giants and gas giants   We report the discoveries of three transiting exoplanets. WASP-91b is a warm
Jupiter (1.34 $M_{\rm Jup}$, 1.03 $R_{\rm Jup}$) in a 2.8-day orbit around a
metal-rich K3 star. WASP-105b is a warm Jupiter (1.8 $M_{\rm Jup}$, 0.96
$R_{\rm Jup}$) in a 7.9-day orbit around a metal-rich K2 star. WASP-107b is a
warm super-Neptune/sub-Saturn (0.12 $M_{\rm Jup}$, 0.94 $R_{\rm Jup}$) in a
5.7-day orbit around a solar-metallicity K6 star. Considering that giant
planets seem to be more common around stars of higher metallicity and stars of
higher mass, it is notable that the hosts are all metal-rich, late-type stars.
With orbital separations that place both WASP-105b and WASP-107b in the
weak-tide regime, measurements of the alignment between the planets' orbital
axes and their stars' spin axes may help us to understand the inward migration
of short-period, giant planets.
  The mass of WASP-107b (2.2 $M_{\rm Nep}$, 0.40 $M_{\rm Sat}$) places it in
the transition region between the ice giants and gas giants of the Solar
System. Its radius of 0.94 $R_{\rm Jup}$ suggests that it is a low-mass gas
giant with a H/He-dominated composition. The planet thus sets a lower limit of
2.2 $M_{\rm Nep}$ on the planetary mass above which large gaseous envelopes can
be accreted and retained by proto-planets on their way to becoming gas giants.
We may discover whether WASP-107b more closely resembles an ice giant or a gas
giant by measuring its atmospheric metallicity via transmission spectroscopy,
for which WASP-107b is a very good target.

27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess