Photodynamics

A differentiable photodynamical model for multiplanet transit light curves, described in Langford & Agol 2025.

Photodynamical models are composed of a dynamical model and a transit (i.e. photometric) model. The currently implemented methods are:

• Dynamical Models:
  • NbodyGradient.jl + PK20: Differentiable 4th-order symplectic N-body integrator combined with an implementation of Parviainen & Korth 2020 (PK20).
• Transit Models:
  • Limbdark.jl: Differentiable quadratic limbdarkened transits.

Getting Started

First, you'll need to add the package. Using the Julia REPL, type ] to enter the package manager.

To add the latest tagged release, run:

pkg> add Photodynamics

If you'd like to use a developement version of the code, add #branch-name:

pkg> add Photodynamics#branch-name

See the Tutorials page for basic usage.