TOI-2535 b: Distant Exoplanet Mysteriously Vanished From View
TOI-2535 b stopped producing the telltale dips in starlight that astronomers used to track it. Researchers say an unseen neighboring planet tugged its orbit out of alignment with its star, and the world is not expected to transit again for at least 30 years.
TOI-2535 b, an exoplanet about 1,000 light-years away, stopped crossing the face of its star after an unseen neighbor tilted its orbit out of alignment, researchers said. The distant exoplanet mysteriously vanished from view during observations by NASA’s Transiting Exoplanet Survey Satellite (TESS).
The planet’s transits — the brief dips in starlight caused as it passes in front of its star — disappeared in March. Researchers say TOI-2535 b is not expected to transit again for at least 30 years.
An orbit that kept shifting
TESS observed TOI-2535 b from April 2019 to March 2026. The planet completes an orbit around its star every 8.25 Earth days.
Its transit times were already irregular: the planet often appeared six hours earlier or later than astronomers expected. Researchers used TESS data to conclude that an unseen planet was tugging on TOI-2535 b, while TOI-2535 b also pulled on its neighbor.
Those gravitational interactions made both planets’ orbits wobble. The shifting orbit eventually tilted TOI-2535 b out of the line of sight between Earth and its star, making its transits disappear.
Samuel Yee of the University of California, Los Angeles, said the system was an unusually strong example of planets affecting each other’s orbits. “The planet's orbit is tilting so quickly that its transit disappeared while we were watching,” Yee said.
What the wobble may reveal
The hidden neighbor may cross the star sooner than TOI-2535 b does. Researchers plan to study what the system’s extreme wobble can reveal about how it formed.
TOI-2535 b is a “hot Jupiter,” a planet that orbits close to its star. One proposed route for hot Jupiters is that they form farther away and gradually move inward within a disk of gas and dust around a young star. Another possibility involves a more turbulent journey, with a planet flung into an elongated orbit before its star pulls it closer.
Yee said the nearby companion points toward slower inward migration for TOI-2535 b. “We may be seeing a formation channel that doesn't happen very often but is very interesting,” he said.
The team’s research was published on November 9 in the Astrophysical Journal Letters.
