The Exomoon Corridor: Half of all exomoons exhibit TTV frequencies within a narrow window due to aliasing

Abstract

Exomoons are expected to produce potentially detectable transit timing variations (TTVs) upon their parent planet. Unfortunately, distinguishing moon-induced TTVs from other sources, in particular planet-planet interactions, has severely impeded its usefulness as a tool for identifying exomoon candidates. A key feature of exomoon TTVs is that they will always be undersampled, due to the simple fact that we can only observe the TTVs once per transit/planetary period. We show that it is possible to analytically express the aliased TTV periodicity as a function of planet and moon period. Further, we show that inverting an aliased TTV period back to a true moon period is fraught with hundreds of harmonic modes. However, a unique aspect of these TTV aliases is that they are predicted to occur at consistently short periods, irrespective of what model one assumes for the underlying moon population. Specifically, 50% of all exomoons are expected to induce TTVs with a period between 2 to 4 cycles, a range that planet-planet interactions rarely manifest at. This provides an exciting and simple tool for quickly identifying exomoons candidates and brings the TTV method back to the fore as an exomoon hunting strategy. Applying this method to the candidate, Kepler-1625b i, reveals that its TTV periodicity centers around the median period expected for exomoons.

Published in MNRAS

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Cited by in corpus (17)

• An Exomoon Survey of 70 Cool Giant Exoplanets and the New Candidate Kepler-1708 b-i
• The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope
• Transit Origami: A Method to Coherently Fold Exomoon Transits in Time Series Photometry
• A search for transit timing variations within the exomoon corridor using Kepler data
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• Cronomoons: origin, dynamics, and light-curve features of ringed exomoons
• The Exomoon Corridor for Multiple Moon Systems
• Transit Light-curves for Exomoons: Analytical Formalism
• Exomoons in Systems with a Strong Perturber: Applications to $\alpha$ Cen AB
• On the Stability of Additional Moons Orbiting Kepler-1625 b
• Updated Studies on Exomoons in the HD 23079 System
• The "Drake equation" of exomoons -- a cascade of formation, stability and detection
• A Transiting Giant on a 7.7-Year Orbit Revealed by TTVs in the TOI-201 System
• The Dynamics of Co-orbital Giant Exomoons -- Applications for the Kepler-1625 b and Kepler-1708 b Satellite Systems
• Transit Duration and Timing Variations from Binary Planets
• Exploring Exoplanet Dynamics with JWST: Tides, Rotation, Rings, and Moons
• The Exoplanet Edge: Planets Don't Induce Observable TTVs with a Dominant TTV Period Faster than Half their Orbital Period