  Optical phase curves of hot Jupiters can reveal global scattering properties.
We implement a Bayesian inference framework for optical phase curves with flux
contributions from: reflected light from a potentially inhomogeneous
atmosphere, thermal emission, ellipsoidal variations, Doppler beaming, and
stellar rotation via a Gaussian process in the time domain. We probe for
atmospheric homogeneity and time-variability using the reflected light
inferences for highly precise Kepler light curves of five hot Jupiters. We also
investigate the scattering properties which constrain the most likely
condensates in the inhomogeneous atmospheres. Cross validation prefers
inhomogeneous albedo distributions for Kepler-7 b and Kepler-41 b, and a weak
preference for inhomogeneity for KOI-13 b. None of the five planets exhibit
significant variations in geometric albedo on one-year timescales, in agreement
with theoretical expectations. We show that analytic reflected light phase
curves with isotropic multiple scattering are in excellent agreement with full
Rayleigh multiple scattering calculations, allowing for accelerated and
analytic inference. In a case study of Kepler-41 b, we identify perovskite,
forsterite, and enstatite as possible scattering species consistent with the
reflected light phase curves, with condensate particle radii in the range
0.01-0.1 micron.
