On the dynamical stability of the proposed planetary system orbiting NSVS 14256825

TL;DR

This study critically examines the proposed planetary system around NSVS 14256825, revealing that the suggested orbits are dynamically unstable on short timescales, challenging previous claims of planetary existence.

Contribution

The paper provides a detailed dynamical analysis showing the proposed planets are unstable, suggesting the need for alternative orbital configurations or further observations.

Findings

Proposed planetary orbits are unstable within less than a thousand years.

A small stable region exists near a 2:1 mean-motion resonance.

Most tested configurations survive only about 1 million years.

Abstract

We present a detailed dynamical analysis of the orbital stability of the two circumbinary planets recently proposed to orbit the evolved eclipsing binary star system NSVS 14256825. As is the case for other recently proposed circumbinary planetary systems detected through the timing of mutual eclipses between the central binary stars, the proposed planets do not stand up to dynamical scrutiny. The proposed orbits for the two planets are extremely unstable on timescales of less than a thousand years, regardless of the mutual inclination between the planetary orbits. For the scenario where the planetary orbits are coplanar, a small region of moderate stability was observed, featuring orbits that were somewhat protected from destabilisation by the influence of mutual 2:1 mean-motion resonance between the orbits of the planets. Even in this stable region, however, the systems tested typically only survived on timescales of order 1 million years, far shorter than the age of the system. Our results suggest that, if there are planets in the NSVS 14256825 system, they must move on orbits dramatically different to those proposed in the discovery work. More observations are clearly critically required in order to constrain the nature of the suggested orbital bodies.