About 1,000 light-years away, a Jupiter-sized planet has done something no planet has ever been seen doing before: it has disappeared. It has not exploded or been swallowed by its star — it is still circling its sun every 8.25 days. But from Earth, it has stopped crossing in front of its star, so to the telescopes that found it, it has vanished.
The planet is called TOI-2535 b. Astronomers led by Samuel W. Yee of UCLA watched it transit its star again and again over seven years of observations from NASA's Transiting Exoplanet Survey Satellite (TESS). Then the transits grew shorter, fainter, and stopped altogether. The team reports the first known "disappearing planet" in the Astrophysical Journal Letters: an unseen neighbour is tilting TOI-2535 b's orbit like a wobbling spinning top, until it no longer passes between its star and us.
A planet that stopped crossing its star
TOI-2535 b is a "hot Jupiter" — a gas giant roughly Jupiter's size, orbiting extremely close to its star. It circles its sun in only 8.25 days. Mercury, the fastest planet in our solar system, takes 88 days per orbit — so this world is more than ten times faster, and far hotter, a giant ball of gas roasted by its star.
TESS first spotted the planet in images from April 2019 to March 2026. But its transits did not run like clockwork. They arrived up to six hours early or late, then grew shorter and shallower, as if only grazing the star's edge. Then, in 2026, they failed to appear at all.
That is the fingerprint of a tilting orbit: each transit a little more off-centre, until the tilt carried the planet's path just above or below the star's disc. The transits stopped not because the planet went anywhere, but because our line of sight no longer lines up with its orbit. Yee called it "the most extreme example we've seen" of planets interacting so strongly.
The wobble will eventually bring TOI-2535 b back: it should transit again in 30 to 50 years. Its hidden neighbour may appear sooner, as its own orbit wobbles toward alignment with Earth.
How the transit trick works — and why it is so fragile
We cannot see TOI-2535 b directly: at 1,000 light-years, its star is a point of light and the planet is lost in the glare. Astronomers use the transit method instead — waiting for a star's brightness to dip slightly as a planet crosses in front of it.
That dip is tiny: a Jupiter-sized planet crossing a Sun-like star blocks roughly one percent of its light. TESS watches hundreds of thousands of stars for exactly those repeating dips.
But the method has a built-in blind spot: a transit is only visible if the planet's orbit lines up almost exactly edge-on to Earth. Hold a coin flat between your eyes and a lamp: edge-on, you see it cross the light; tilt it a degree or two, and it passes above or below the lamp, unseen. For a close-in planet the odds of alignment are roughly one in ten; for a planet as far from its star as Earth, about one in two hundred.
The transit method is a lottery, and every planet it finds is a winner. TOI-2535 b won in 2019 — and we then watched it lose in real time, the first time astronomers have caught a planet's transits switching off while they looked. It is the same geometry that makes eclipses on Earth rare, as co-author Erik Petigura put it: "If the Moon's orbit around the Earth was perfectly aligned with the Earth's orbit around the Sun, we would see an eclipse every month. But because the Moon's orbit is tilted, eclipses are less common."
The wobble: what nodal precession really means
The technical name for this is nodal precession. The picture is simple, and you have probably seen it in your kitchen. Spin a top and it does not stay upright: its axis slowly traces a circle while it keeps spinning at the same speed.
A planet's orbit can do the same. The orbit is a flat ring with a direction — the way it is tilted in space — and when a second planet tugs on it, the ring's tilt slowly rotates, like a top's axis. The planet keeps racing around its star — but from Earth, its path across the star's face drifts toward the edge, then off it.
What is remarkable is the speed. Orbital tilts usually change over thousands or millions of years, but here the two planets pull on each other so hard that the change is visible within one research career: seven years from first transit to none at all. Most exoplanet systems are assumed stable, like clockwork. TOI-2535 b shows the clockwork can wobble — and fast. Closer to home, the Moon is slowly shrinking, its surface cracking into thousands of faults.
The hidden neighbour pulling the strings
The most tantalising part is the planet we have not seen: nobody has directly observed TOI-2535 b's companion. Its existence is inferred from TOI-2535 b's behaviour — transits up to six hours early or late, shrinking dips, then disappearance. Only a massive neighbour on a tilted orbit can explain a wobble this strong. The team confirmed TOI-2535 b itself is an extremely hot, Jupiter-sized planet using the WIYN 3.5-metre telescope at Kitt Peak National Observatory in Arizona.
The two planets are not just tilting one orbit; they are tilting each other. Gravity is mutual: as the neighbour drags TOI-2535 b's orbit around, TOI-2535 b drags the neighbour's around too. So the hidden planet may appear sooner than its companion returns: its orbit is swinging toward alignment with Earth, and when it crosses that line, its transits will switch on — a planet appearing out of nowhere, the mirror image of the one that disappeared.
How did a hot Jupiter end up like this?
The discovery also hints at an old puzzle: how hot Jupiters form at all. Gas giants need large amounts of ice to form, and ice only exists far from a star, where it is cold enough to freeze. A Jupiter-sized planet should be born far out — yet here is one in an 8.25-day orbit, far too close for ice ever to have existed. Something must have moved it inward: a process called migration.
There are two main ideas about how that happens. In the first, a violent event — a near-collision, for example — throws the planet onto a stretched-out orbit, which the star's gravity then pulls in and rounds off. In the second, the planet spirals inward gently with the other planets in the disc of gas and dust around the young star. The gentle version should leave a flat, tidy system; the violent version, a mess of tilted, eccentric orbits.
The wobble points to the messier end of that spectrum — but with a twist. "Because TOI-2535 b has a close neighbour, it probably migrated by slowly spiralling in instead of getting flung in," Yee said. "We may be seeing a formation channel that doesn't happen very often but is very interesting." Had the planet been violently flung inward, its neighbour would probably have been scattered away. A massive, tilted neighbour still being there suggests the two moved inward together, their orbits tilting as they went. The wobble we see today is a fossil: a record of how this system was assembled.
How many planets have we already missed?
This is where the discovery stops being about one planet and starts being about all of them. If a planet's transits can switch off in seven years, the census built with the transit method is not a fixed photograph — it is a snapshot, and some planets in it have already moved on.
TESS and Kepler have found thousands of planets, feeding estimates of how common planets are — how many stars have them, how many are Earth-sized, how many sit in the habitable zone. Those estimates assume the transiting planets we see are representative, and the ones we miss are missed randomly, because their orbits point the wrong way.
TOI-2535 b shows the misses are not always random, or permanent: a planet can be visible for a decade and invisible for the next fifty. Somewhere in the data, there are surely planets that transited when Kepler looked in 2010 and had stopped by the time TESS looked in 2020 — planets counted once and never again, or planets already invisible when we first looked, due back only decades from now. The effect is probably rare — it needs a close, massive, tilted neighbour — but it is no longer zero, or theoretical.
Every telescope sees the universe through its own narrow window — a slice of sky, a range of wavelengths, a moment in time. Instruments like the Euclid space telescope, whose first discoveries are already mapping the dark universe, and radio observatories such as CHIME, which detected the faint hydrogen glow of the early universe, each open a different window. TOI-2535 b warns that even the windows we trust most can close without warning — and the planets we know may be only the ones lined up right now.
What happens next
For now, TOI-2535 b is gone from the transit record. Astronomers will not simply wait thirty to fifty years, though. The planet still tugs on its star, so precise measurements of the star's motion — the radial velocity method — can track the system while the transits are off.
The neighbour's transits may even switch on first: its orbit is wobbling in the opposite sense, and the team's models suggest it could align with Earth well before TOI-2535 b returns. If that happens, astronomers get a second planet for the price of one — one world vanishing as another appears.
Why this discovery matters
TOI-2535 b is not habitable or Earth-like. But it is the first time we have watched a planet disappear and understood exactly why. The universe is often presented as clockwork — regular, predictable, eternal — yet this discovery shows the clockwork has moving parts we are only beginning to see, and some move fast enough to catch us by surprise.
A planet vanished in seven years; it will return in thirty to fifty. In that slow wobble is the story of how two giant worlds ended up where they are. When the transits switch back on, a new generation of astronomers will be waiting — watching the rest of the sky a little more carefully, knowing now that planets do not only appear. Sometimes, they disappear too.
Sources
- First known 'disappearing planet' has a neighbor that makes it wobble like a top — UCLA Newsroom, 9 November 2026
- Samuel W. Yee et al., "A TESS Disappearing Act: The Vanishing Transits of TOI-2535 b", The Astrophysical Journal Letters (2026)
- First known 'disappearing planet' has a neighbor that makes it wobble like a top — Phys.org, 9 November 2026