Using seven years of data from NASA’s Transiting Exoplanet Survey Satellite (TESS), plus ground-based telescopes, University of California, Los Angeles astronomer Samuel Yee and colleagues report that the hot Jupiter TOI-2535b has stopped passing in front of its star. It is the first confirmed planet around a single star whose transits have been directly observed to disappear.
An artist’s impression of a hot-Jupiter exoplanet. Image credit: Sci.News.
TOI-2535 is an old, early K-type dwarf star located 1,000 light-years away in the constellation of Corvus.
TOI-2535b whips around the star in only 8.25 days — 10 times faster than the 88 days that Mercury takes to go around our Sun once.
When TESS first observed the system in 2019, the planet crossed near the middle of the star’s disk.
Over the following years, its path shifted steadily toward the stellar edge, becoming grazing before disappearing entirely.
The planet’s impact parameter, which measures how far from the star’s center the transit occurs, changed at about 0.16 per year.
This is the fastest such change ever seen for an exoplanet around a single star. TESS data from early 2026 showed no sign of a transit.
The planet’s transit timing was also erratic, drifting by as much as six hours from a regular schedule, among the largest timing variations known for a hot Jupiter.
The likely culprit, according to the current study, is a second, unseen planet.
Modeling of the timing and shape changes, combined with radial-velocity measurements from the NEID spectrograph on the WIYN 3.5-m telescope at Kitt Peak National Observatory, suggests a nearby companion of roughly Saturn mass or greater, probably locked in a mean-motion resonance with TOI-2535b.
The two planets’ orbits appear tilted relative to each other by at least about 5 degrees, causing their orbital planes to precess like wobbling tops, with periods of decades. This tilt carried the hot Jupiter’s orbit out of our line of sight.
If confirmed, TOI-2535b would be a rare example of a hot Jupiter with a nearby giant companion, a pairing likely formed through migration in the planet-forming disk rather than the high-eccentricity route thought to produce most hot Jupiters.
“Because TOI-2535b has a close neighbor, it probably migrated by slowly spiraling in instead of getting flung in,” Dr. Yee said.
“We may be seeing a formation channel that doesn’t happen very often but is very interesting.”
The discovery is reported in a paper in the Astrophysical Journal Letters.
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Samuel W. Yee et al. 2026. A TESS Disappearing Act: The Vanishing Transits of TOI-2535b. ApJL 1011, L60; doi: 10.3847/2041-8213/aeb4a4
