Decoupling Phase Variations in Multi-Planet Systems

TL;DR

This paper discusses how phase variations in multi-planet systems can be complex and confounded by other planetary signals, but can be disentangled using specific techniques, with applications demonstrated on Kepler systems.

Contribution

It introduces methods to decouple phase variations in multi-planet systems, addressing confusion caused by additional planetary signals, and demonstrates these techniques on Kepler data.

Findings

Decoupling of phase signals is feasible with the proposed methods.

Short-period and non-transiting planets introduce correlated noise and trends.

Application to Kepler systems validates the approach.

Abstract

Due to the exquisite photometric precision, transiting exoplanet discoveries from the Kepler mission are enabling several new techniques of confirmation and characterization. One of these newly accessible techniques analyzes the phase variations of planets as they orbit their stars. The predicted phase variation for multi-planet systems can become rapidly complicated and depends upon the period, radius, and albedo distributions for planets in the system. Here we describe the confusion which may occur due to short-period terrestrial planets and/or non-transiting planets in a system, which can add high-frequency correlated noise or low-frequency trends to the data stream. We describe these sources of ambiguity with several examples, including that of our Solar System. We further show how decoupling of these signals may be achieved with application to the Kepler-20 and Kepler-33 multi-planet systems.