Friday, January 19, 2024 at 12:15 pm

JILA Foothills Room

Daniel Yahalomi, Columbia University

"From Wobbles to Worlds: Exploring the Orbital Landscape of Planet-Planet TTVs"

Abstract:

The orbital periods of unseen perturbing planets inferred via transit timing variations (TTVs) detected in single planet systems are notoriously multi-modal. Using TTVFast for planet-planet N-body simulations and a modified lomb-scargle periodogram with multiple periodic components, we can decompose a planet-planet TTV signal into several periodic components, and then use this to down-select the allowed modes to a subset, even a unique solution. There are hundreds of single-planet systems in Kepler data that show unexplained yet significant periodic TTVs. Using this periodic decomposition method, one can then aim to investigate these hundreds of single planet Kepler TTVs in order to statistically predict whether the TTVs are induced by an unseen perturbing planet or by another astrophysical source (ie. a moon or stellar activity). Additionally, we present our finding that a perturbing planet that is not highly eccentric, will never induce a TTV with an observed dominant period less than half its own orbital period. This “exoplanet edge” is the manifestation of an observational alias of the true TTV period. The presence of an anomalous dominant TTV period, in a not highly eccentric two-planet system (ie. one that doesn't fall on the exoplanet edge), would demonstrate that there exists additional mass in the system, besides the two known exoplanets. We identify several two-planet systems, in Kepler data, that don't lie on the exoplanet edge, and discuss several possible explanations for additional mass in the system.

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