For seven years, astronomers watched a Jupiter-sized planet about 1,000 light-years away dim its star on a tight 8.25-day schedule. In 2026 the dimming stopped. The planet, TOI-2535 b, has not been destroyed or ejected; its orbit has tilted out of Earth’s line of sight, and the team that tracked it expects the next crossing in 30 to 50 years.
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A group led by Samuel Yee and Erik Petigura of the University of California, Los Angeles reported the result in The Astrophysical Journal Letters, with a UCLA news release dated Nov. 9. Yee, a 51 Pegasi b Postdoctoral Fellow, is the corresponding author. The planet is a hot Jupiter, a gas giant that circles its star roughly ten times faster than Mercury circles the Sun, whose own orbit takes 88 days.
Seven years of TESS transits that drifted, shrank and ended
NASA’s Transiting Exoplanet Survey Satellite, known as TESS, identified the planet in observations of the TOI-2535 system taken from April 2019 to March 2026, according to the UCLA release and the matching EurekAlert posting. TESS finds planets by catching the small dips in starlight as a world passes in front of its star. Precise follow-up from the WIYN 3.5-meter telescope at Kitt Peak National Observatory in Arizona pinned down the planet’s size, which is Jupiter-like, and its extreme heat.
The transits never ran on a clean clock. They arrived as much as six hours early or late, and over time they grew shorter and shallower before stopping completely in 2026. That slow fade is the signature the team used to rule out simple explanations such as a faded star or a bad instrument. A planet that is merely hidden behind its star would still transit; here the geometry itself changed.
An unseen neighbor and an orbit that wobbles like a top
The explanation is gravity from a second, unseen planet whose orbit is tilted relative to the first. The pull from the neighbor makes both orbits wobble like a spinning top, and the wobble tilts TOI-2535 b out of alignment with the line of sight from Earth. Yee described it as the most extreme example the team has seen, because the two planets interact so strongly. The neighbor has not been observed directly; its existence is inferred from the changing transits. Tech Times adds that the mechanism is a precession of the orbit driven by the companion, and that it projects transits returning between 2056 and 2076, a span that matches the 30-to-50-year window from the release.
Petigura offered an everyday comparison from the Moon. If its orbit were aligned with Earth’s path around the Sun, the Moon would produce an eclipse every month; because its orbit is tilted, eclipses are rare. TOI-2535 b is in a similar position, except that its tilt is changing and carrying it away from alignment.
What a tilted hot Jupiter says about how such planets form
Hot Jupiters have long puzzled planet-formation theorists, because standard models suggest giant planets need a lot of ice to form and that ice exists far from a star. Two paths bring them close in. In a violent version, a planet is knocked onto an elongated orbit, perhaps by a near-collision, and the star then pulls it inward. In a gentler version, it migrates inward through the protoplanetary disc together with other planets, which would normally leave a flat system with aligned orbits. The tilt seen here would seem to favor the violent route, yet Yee said the presence of a close neighbor means the planet probably migrated by slowly spiraling in rather than being flung inward. The finding suggests neighbors can interact and tilt each other after the fact.
It is not the only planet expected to slip out of view. A separate paper in the Publications of the Astronomical Society of Japan, led by Noriharu Watanabe of the University of Tokyo, reports that TOI-1355 b, a hot Jupiter about 805 light-years away on a 2.17-day orbit, has an orbit tilting slowly enough that it should become unobservable from Earth around 2033. TOI-2535 b is the more abrupt case, with transits that disappeared inside the span of a single survey.
The timeline shows how quickly the planet’s geometry changed. Tech Times reports that the system sits among more than 6,000 known exoplanets, and TESS followed it for nearly seven years, from April 2019 to March 2026. The early transits looked routine, apart from timing shifts of up to about six hours. By 2026 they were gone. Astronomers had not previously seen a companion planet, rather than the spin of the star, erase a hot Jupiter’s transits, according to Tech Times, which makes the system a useful test case for catalogs that assume transits stay put.
Several things remain unsettled. The hidden neighbor has no confirmed mass or distance, so the 30-to-50-year return is a projection tied to a model, and any change in the companion’s orbit estimate could move it. The team says the neighbor may become visible sooner than the transits resume, which would let astronomers test the model well before the next crossing arrives. The peer-reviewed paper is published at IOP Science, where the orbital solution is laid out in full.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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