Solar System Moons as Analogs for Compact Exoplanetary Systems

TL;DR

This paper compares the scaled sizes and separations of Solar System moons and Kepler exoplanets, revealing similar correlations that suggest commonalities and differences in their formation and evolution.

Contribution

It provides a quantitative comparison of Solar System moons and exoplanets, highlighting their similar scaled distributions and implications for formation theories.

Findings

Solar System moons and Kepler planets show similar scaled size-separation correlations.

Differences in correlation gradients suggest varied formation or dynamical histories.

The study offers insights into the evolution of compact planetary and moon systems.

Abstract

The field of exoplanetary science has experienced a recent surge of new systems that is largely due to the precision photometry provided by the Kepler mission. The latest discoveries have included compact planetary systems in which the orbits of the planets all lie relatively close to the host star, which presents interesting challenges in terms of formation and dynamical evolution. The compact exoplanetary systems are analogous to the moons orbiting the giant planets in our Solar System, in terms of their relative sizes and semi-major axes. We present a study that quantifies the scaled sizes and separations of the Solar System moons with respect to their hosts. We perform a similar study for a large sample of confirmed Kepler planets in multi-planet systems. We show that a comparison between the two samples leads to a similar correlation between their scaled sizes and separation distributions. The different gradients of the correlations may be indicative of differences in the formation and/or long-term dynamics of moon and planetary systems.