Many exoplanets exhibit wobbles in their orbits, hindering understanding of their systems. A new research paper unveils 'exoplanet edges' – boundaries in a landscape of transit timing variations – offering insights into the causes of these wobbles. These edges may facilitate discovery of thousands of new exoplanets and potentially reveal the presence of exomoons.
Exoplanet Wobbles
• 00:00:05 Thousands of exoplanets exhibit wobbles, defying Newton's laws, and their causes remain largely unknown. These wobbles are detected through transit timing variations (TTVs), irregularities in the timing of planetary transits. While initially thought to be caused by additional planets, other possibilities like exomoons exist, making it challenging to understand the systems.
Kepler Mission
• 00:01:44 NASA's Kepler mission discovered thousands of exoplanets, but primarily those close to their stars. A large percentage of single-planet Kepler systems show strong evidence of wobbles, suggesting potentially thousands of undetected exoplanets in the data. Kepler's limitations prevented the observation of planets further from their stars, especially on the outskirts of systems.
TTV Landscape
• 00:07:30 Simulations of various planetary systems reveal a complex landscape of possible solutions for TTVs. This landscape makes it difficult to determine the orbital period of the perturbing planet causing the wobbles when only one planet is visible in the transit. The complex landscape visually illustrates why the problem of understanding exoplanet wobbles has proven so challenging.
Exoplanet Edges
• 00:08:34 The 'exoplanet edges' are two straight lines in the TTV landscape that behave differently than the other curves. These edges are explained by the effect of tides on the orbits and by an observational effect called aliasing, which influences the observed wobble frequencies. The discovery of these edges provides a crucial tool to understand exoplanet systems.
Applications of Edges
• 00:16:00 The exoplanet edges provide a new method to constrain the possible solutions for exoplanet systems. For instance, the lower edge acts as an impossible boundary for TTVs in two-planet systems. Deviation from this boundary suggests a third body in the system, making it a useful tool for detecting exomoons. These edges also help to constrain solutions in single-planet systems by reducing the number of possibilities, paving the way for new discoveries.