Chaos in multiplanetary extrasolar systems

Abstract

ABSTRACT Here, we present an initial look at the dynamics and stability of 178 multiplanetary systems that are already confirmed and listed in the NASA Exoplanet Archive. To distinguish between the chaotic and regular nature of a system, the value of the Mean Exponential Growth factor of Nearby Orbits (MEGNO) indicator for each system was determined. Almost three-quarters of them could be labelled as long-term stable. Only 45 studied systems show chaotic behaviour. We consequently investigated the effects of the number of planets and their parameters on the system stability. A comparison of results obtained using the MEGNO indicator and machine-learning algorithm SPOCK (Stability of Planetary Orbital Configuration Klassifier) suggests that the SPOCK could be used as an effective tool for reviewing the stability of multiplanetary systems. A similar study was already published by Laskar and Petit. We compared their analysis based on the AMD (Angular Momentum Deficit) criterion with our results. The possible discrepancies are discussed.