On the Scaling and Spacing of Extra-Solar Multi-Planet Systems

TL;DR

This study examines whether certain exoplanet multi-planet systems follow the angular-momentum-deficit model's scaling and spacing rules, revealing insights into their formation histories and the effects of gaseous environments.

Contribution

It analyzes multiple exoplanet systems to identify which adhere to the angular-momentum-deficit model and how gaseous effects influence their configurations.

Findings

GJ 667C, HD 215152, HD 40307, Kepler-79 follow the model.

Some systems were once aligned with the model but were scattered by gaseous effects.

Certain systems do not follow the model regardless of gaseous environment.

Abstract

We investigate whether certain extra-solar multi-planet systems simultaneously follow the scaling and spacing rules of the angular-momentum-deficit model. The masses and semi-major axes of exoplanets in ten multi-planet systems are considered. It is found that GJ 667C, HD 215152, HD 40307, and Kepler-79 systems are currently close to configurations of the angular-momentum-deficit model. In a gas-poor scenario, GJ 3293, HD 141399, and HD 34445 systems are those which had a configuration of the angular-momentum-deficit model in the past and get scattered away due to post gaseous effects. In addition, no matter in gas-free or gas-poor scenario, 55 Cnc, GJ 876, and WASP-47 systems do not follow the angular-momentum-deficit model. Therefore, our results reveal important formation histories of these multi-planet systems.