TOI-2535b, a hot Jupiter, stopped transiting its star during 7 years of TESS observations
Astronomers report the first confirmed planet around a single star whose transits were observed to vanish. An unseen second planet may be tilting its orbit.
A team led by Samuel W. Yee at the University of California Los Angeles reported the hot Jupiter TOI-2535b, the first confirmed planet orbiting a single star whose transits have been directly observed to disappear. The paper appeared on 9 November 2026 in The Astrophysical Journal Letters (doi.org) iop.org
doi.orgiop.orgOpen source ↗. Over 7 years of photometry from NASA's Transiting Exoplanet Survey Satellite (TESS), the planet's transit chord crossed the stellar disk and eventually moved off it.
Transits that drifted away
TOI-2535b is a gas giant that orbits very close to its star. The system is about 1,000 light-years away, and the planet completes an orbit in a little over eight days. TESS collected observations from 2019 to March 2026, and the 3.5-meter WIYN telescope at Kitt Peak in Arizona helped track the planet.
The transits were irregular. Some arrived up to six hours earlier or later than expected, and over time the dips in starlight became shallower and shorter, as if the planet were passing closer and closer to the star's edge. By 2026 the transits were no longer seen in the observations. The planet can still circle the star, passing just above or below its disk from our point of view.
A possible hidden neighbor
Transit timing and transit duration gave two separate clues. The first showed that the planet's motion was being disturbed, and the second helped reveal how its path across the star had changed. The authors point to another planet as a likely explanation: its gravity could shift the timing of the transits while gradually turning the plane of the giant planet's orbit iop.org
doi.orgiop.orgOpen source ↗. That planet has not been observed directly.
A close neighbor would also bear on the giant's history. One way to form a hot Jupiter is to send a giant planet inward on a stretched-out orbit, which could disrupt nearby worlds, so a surviving companion would make that route harder to explain here.
The team's models suggest that TOI-2535b might begin transiting again in 30 to 50 years. The estimate depends on the proposed orbits, and the suspected neighbor could cross the star sooner if its own path swings into view. Detecting it would allow a test of whether its gravity explains both the timing changes and the disappearance of the transits.
