STEEP: Coupled Stellar-Tidal Evolution of Binary Orbits

Overview

This example examines the coupled stellar-tidal evolution of binary orbits. This figure, adapted from Graham et al. in prep, demonstrates how the early transfer of angular momentum from the stellar spins into the orbit expands the binary orbit. This expansion can destabilize any circumbinary planets that tend to orbit near the dynamical stability limit, also known as the critical semi-major axis. This effect, deemed STEEP (Stellar-Tidal Ejection of ExoPlanets) was first studied in Fleming et al. (2018).

Date	02/28/20
Author	David Fleming
Modules	EQTIDE STELLAR
Approx. runtime	5 minutes

To run this example

python makeplot.py <pdf | png>

Expected output

Critical semi-major axis (top), orbital period (middle), and orbital eccentricity (bottom) vs. time for four solar twin stellar binaries undergoing coupled stellar-tidal evolution. This simulation explores how an evolving radius of gyration (Dynamic r_g) can supply additional angular momentum to the binary orbit vs the constant (Static) r_g case, further expanding the binary orbit, potentially destabilizing and CBPs that may orbit near the dynamical stability limit.