A hot Jupiter that astronomers watched for seven years suddenly stopped showing up, and now we know why.
The disappearing planet TOI-2535 b has become the first exoplanet ever caught losing its visible transit in real time, according to a UCLA-led study released in November 2026. The gas giant sits about 1,000 light-years from Earth and did not vanish or break apart. Its orbit simply tilted out of the narrow path needed for telescopes to see it cross its star.
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How The Disappearing Planet TOI-2535 b Was First Spotted
NASA's Transiting Exoplanet Survey Satellite, known as TESS, began watching the TOI-2535 star system back in April 2019. For years, the spacecraft caught a steady, repeating dip in starlight every time TOI-2535 b swept across the face of its star. That dip happened like clockwork, roughly every 8.25 days, which is the planet's full orbit around its sun.
Since the planet circles so close to its star, scientists classify it as a hot Jupiter, a type of gas giant known for blistering surface temperatures and tight, fast orbits. For a long stretch, nothing about TOI-2535 b seemed unusual. It looked like a textbook transiting exoplanet, the kind astronomers rely on to measure size, orbit, and other basic traits.
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Why The Transits Started Acting Strange
Things changed gradually, then all at once. Instead of arriving at the exact expected moment, the planet's transits began showing up as much as six hours early or late. On top of that timing drift, each transit grew shorter and fainter than the one before it, a sign that something was reshaping the system's geometry.
By March 2026, the dips disappeared completely. TESS kept watching, but TOI-2535 b never crossed its star again during the observation window. That left scientists with a real puzzle: had the planet been destroyed, flung out of the system, or was something else going on entirely.
The research team, whose findings appeared in the Astrophysical Journal Letters, concluded the planet is still there. A second, previously undetected planet in the same system is tugging on TOI-2535 b with enough gravitational force to tilt its orbital plane. As that tilt shifted, the planet's path across the sky moved further and further from Earth's line of sight until the transit vanished altogether.
A Cosmic Wobble Caught In The Act
One line from the research coverage captured just how rare this is. Researchers described it this way: "This is the most extreme example we've seen because the two planets are interacting so strongly. The planet's orbit is tilting so quickly that its transit disappeared while we were watching." That kind of rapid, observable shift is almost never caught happening live.
The mechanism at play is called orbital precession, where gravity from a neighboring planet causes an orbit to wobble like a spinning top losing its balance. Because the two planets' orbital planes are mutually inclined, each one pulls and nudges the other. Over time, that nudge was strong enough to drag TOI-2535 b's transit path completely off Earth's view within the seven-year TESS campaign.
Multiple signs pointed to this explanation rather than a telescope glitch or a planet that had somehow ceased to exist. The six-hour timing swings, the shrinking transit depth, and the eventual total disappearance all lined up with a changing orbital angle, not a broken instrument or a destroyed world.
What Comes Next For Astronomers Watching This System
Researchers now expect TOI-2535 b to stay hidden from transit view for a long time. Current estimates suggest it won't cross its star again, from Earth's vantage point, for at least around 30 years, with some models stretching that window out to 50 years.
There is a silver lining, though. The unseen neighboring planet responsible for the wobble might transit the star sooner than TOI-2535 b does. If that happens, astronomers could directly detect the mystery planet for the first time, using its own dip in starlight rather than inferring its presence through gravity alone.
Why This Discovery Matters Beyond One Star System
This case is being called the first confirmed instance of a known transiting planet disappearing from observation due to orbital tilt, and it carries a bigger lesson for exoplanet science. Transit surveys work by catching planets during a brief alignment window. If a planet's orbit shifts, as TOI-2535 b's did, short observation campaigns could completely miss worlds that are very much still there.
That is why the seven-year TESS data set mattered so much here. A shorter study might have simply logged TOI-2535 b as lost or unconfirmed. Instead, long-term monitoring revealed the timing drift and shrinking transit shape that exposed the real cause. Scientists now plan to keep watching the system, hoping to spot the hidden companion and confirm exactly how these two planets are reshaping each other's paths through space.
