ORCHARD: A General Planetary Evolution Code

TL;DR

ORCHARD is a comprehensive, publicly available planetary evolution code capable of modeling a wide range of planets from terrestrial to gas giants, incorporating complex physics and diverse atmospheric conditions.

Contribution

It introduces a unified, flexible tool that models planetary evolution and structure across a broad mass range, supporting inhomogeneous and non-adiabatic processes.

Findings

Supports modeling from 0.5 Earth masses to 10 Jupiter masses.

Includes advanced equations of state for various planetary materials.

Handles diverse atmospheric boundary conditions.

Abstract

We present \texttt{ORCHARD}, a publicly available planetary evolution code based on the gas giant evolution code, \texttt{APPLE}, capable of modeling the evolution and structures of terrestrial, super-Earth, sub-Neptune, Neptune, and gas giant planets and exoplanets from 0.5 M$_\oplus$ to 10 M$_J$. It supports not only the inhomogeneous and non-adiabatic evolution of gas giants and sub-Neptunes, but also the solidification of the mantles and cores of terrestrial planets, sub-Neptunes, and super-Earths. \texttt{ORCHARD} incorporates a state-of-the-art hydrogen-helium equation of state, ``metal" equations of state (water, ice mixtures, enstatite/perovskite, olivine/forsterite, iron), and atmospheric boundary conditions ranging from detailed non-gray radiative transfer models for Solar System giants to irradiated sub-Neptune atmospheres and bare rocky surfaces. The purpose of \texttt{ORCHARD} is to provide the scientific community with a flexible, unified tool for modeling planetary structures and evolution across the entire mass continuum of general astrophysical and planetary interest.