Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Dark Planets of the WASP-47 Planetary System   Exoplanet discoveries have demonstrated a vast range of planetary system
architectures. The demographic of compact planetary systems are especially
interesting from the perspective of planetary formation and the evolution of
orbital dynamics. Another interesting demographic is that of giant planets in
eccentric orbits, since these planets have likely had a dynamical history
involving planet-planet scattering events. The WASP-47 system is particularly
fascinating since it combines these two demographics, having both compact
planetary orbits and a giant planet on an eccentric orbit within the system
Habitable Zone. Here we provide an analysis of the WASP-47 system from the
perspective of atmospheric detection and characterization. We discuss the
system architecture and the potential for additional long-period planets. We
simulate expected phase variations as a function of planet orbital phase for
the system due to the combined effect of the planets. We present analysis of
precision photometry of WASP-47 from the K2 mission, phased on each of the
planets. The analysis rules out the detection of phase signatures for the two
inner-most planets, enabling constraints upon their albedos and atmospheric
properties. Our study concludes that WASP-47b is an example of a "dark" planet
with a tentative geometric albedo of 0.016 and a 1$\sigma$ upper limit of 0.17.
The WASP-47e data are consistent with a broad range of albedos, but also show
early evidence of having a relatively low albedo. The growing number of dark,
short-period giant planets provide the framework of an ideal sample for
studying low albedo dependence on atmospheric composition.

25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg