Transit Timing Variations Confirmed in Ultra-Hot Jupiter TOI-2109 b via JWST and HST
JWST and HST photometry confirm TTVs in TOI-2109 b, tightening dynamical constraints on unseen companions. The result validates timing methods for extreme planets and supports expanded JWST TTV programs. Limitations include sparse phase coverage and assumptions of coplanar orbits.
The study combined 12 transit observations across JWST NIRSpec and HST WFC3 to measure mid-transit times with 20-second precision. Analysis revealed a 3.2-minute TTV signal inconsistent with a single-planet model at 4.8 sigma, pointing to gravitational perturbations from an unseen body. Orbital fitting yielded a companion mass upper limit of 0.3 Earth masses at the 2:1 resonance. This marks the first robust TTV detection in an ultra-hot Jupiter, extending the technique beyond cooler systems where atmospheric scale heights are smaller.
JWST Cycle 3: TTV amplitude will exceed 5 minutes in follow-up data within 18 months if the perturber is confirmed.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2609.26849)
- [2]Supporting Source(https://ui.adsabs.harvard.edu/abs/2023AJ....165..120S)