  "exoplanet" is a toolkit for probabilistic modeling of astronomical time
series data, with a focus on observations of exoplanets, using PyMC3 (Salvatier
et al., 2016). PyMC3 is a flexible and high-performance model-building language
and inference engine that scales well to problems with a large number of
parameters. "exoplanet" extends PyMC3's modeling language to support many of
the custom functions and probability distributions required when fitting
exoplanet datasets or other astronomical time series. While it has been used
for other applications, such as the study of stellar variability, the primary
purpose of "exoplanet" is the characterization of exoplanets or multiple star
systems using time-series photometry, astrometry, and/or radial velocity. In
particular, the typical use case would be to use one or more of these datasets
to place constraints on the physical and orbital parameters of the system, such
as planet mass or orbital period, while simultaneously taking into account the
effects of stellar variability.
