Plate Nº 69 · recorded November 11, 2026
Space & AstronomyReported finding
Astronomers Watch an Exoplanet's Transits Vanish for the First Time
TESS watched hot Jupiter TOI-2535b slide from the middle of its star to the edge and vanish — the first such disappearance seen around a single star. A hidden Saturn-mass world is the suspect.
By Marcus Bennett3 min read646 words
In brief
- TOI-2535b orbits its star every 8.25 days, 10 times faster than Mercury orbits the Sun
- Its impact parameter shifted by about 0.16 per year, the fastest ever seen for a single-star exoplanet
- TESS observed the transit disappear between 2019 and early 2026
- A hidden companion of roughly Saturn mass or greater is the suspected cause
- The system lies 1,000 light-years away in the constellation Corvus
For the first time, astronomers have directly watched a planet around a single star stop crossing in front of it. UCLA astronomer Samuel Yee and colleagues report in the Astrophysical Journal Letters that the hot Jupiter TOI-2535b, 1,000 light-years away in the constellation Corvus, no longer passes across its star's face as seen from Earth.
The finding rests on seven years of observations from NASA's Transiting Exoplanet Survey Satellite (TESS), backed by ground-based telescopes. TESS first caught the planet crossing near the middle of the star's disk in 2019. Year by year, the transit path drifted toward the stellar edge, turned into a grazing clip of the limb, and then vanished. Data from early 2026 show no transit at all.
How fast did the orbit shift?
The numbers tell the story. TOI-2535b circles its star every 8.25 days — ten times faster than Mercury's 88-day lap around the Sun. Its impact parameter, a measure of how far from the star's center the transit lands, changed at about 0.16 per year. That is the fastest such shift ever recorded for a planet around a single star.
The transit timing also wandered. Arrivals drifted by as much as six hours from a strict schedule, ranking among the largest timing variations known for any hot Jupiter — the class of Jupiter-like planets orbiting scorchingly close to their stars.
In plain terms: the planet's orbital plane tilted out of our line of sight within a handful of years.
What caused the disappearance?
The likely culprit is a second, unseen planet. Yee's team modeled the timing and shape changes and combined them with radial-velocity measurements — a technique that detects the wobble a planet induces in its star — from the NEID spectrograph on the WIYN 3.5-meter telescope at Kitt Peak National Observatory.
The data point to a nearby companion of roughly Saturn's mass or greater, probably locked in a mean-motion resonance with TOI-2535b, meaning the two planets' orbital periods form a simple ratio that keeps repeating their gravitational tug on each other.
The two orbits appear tilted relative to each other by at least about 5 degrees. That misalignment makes their orbital planes precess — wobble like spinning tops — over periods of decades. The wobble carried the hot Jupiter's path off the star's disk and out of view.
Why does the hidden companion matter?
If confirmed, the companion would make TOI-2535b a rare specimen: a hot Jupiter with another giant planet parked nearby. Most hot Jupiters are thought to arrive through a violent route — a close encounter flings them onto a stretched, eccentric orbit that the star's tides then shrink. A close neighbor rules that out.
"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 star itself, TOI-2535, is an old, early K-type dwarf — a cool, orange star smaller than the Sun.
What are the caveats?
The companion planet remains unconfirmed; the Saturn-mass estimate comes from modeling and radial-velocity data, not direct detection. The resonance and the 5-degree tilt are inferences from the same models, and the precession periods of decades mean astronomers will need years of further monitoring to trace the full cycle.
Even so, the vanishing act itself is secure: TESS watched the transit move, graze, and disappear across seven consecutive years of data. The discovery paper is published as Samuel W. Yee et al. 2026, "A TESS Disappearing Act: The Vanishing Transits of TOI-2535b," Astrophysical Journal Letters 1011, L60.
A planet that hides from our telescopes may reveal more about how hot Jupiters form than one that never moves.
via sci.news (Source)
More from Marcus Bennett
Show full bio
News editor covering regulation, policy and their impact on general science news at SciBeat.
370 articles
Nearby plates
- A Giant Planet Vanished From View — And a Hidden Neighbor May Be Why
- First known “disappearing planet” traced to an orbit-tilting neighbor
- Astronomers Watch a Hot Jupiter Vanish From View Mid-Observation
- Astronomers Confirm Youngest Known Planet, Under 1 Million Years Old
- Voyager 1 to reach 1 light-day from Earth in November 2026