Planet 1,000 light-years away mysteriously vanishes before astronomers’ eyes

UCLA-led astronomers have identified TOI-2535 b as the first known "disappearing planet," a hot Jupiter roughly 1,000 light-years from Earth that stopped transiting its host star after seven years of regular observation. The planet, which orbits its star every 8.25 days — ten times faster than Mercury orbits the Sun — was detected by NASA's Transiting Exoplanet Survey Satellite (TESS) between April 2019 and March 2026. Over that period, researchers noticed the transits did not follow a regular schedule, arriving up to six hours early or late, and grew progressively shorter and shallower until they ceased entirely in 2026.

The disappearance is not literal. According to the study published in Astrophysical Journal Letters on November 9, gravitational interaction with an unseen neighboring planet is tilting TOI-2535 b's orbit, causing both planets to wobble like spinning tops. This wobble eventually tilted TOI-2535 b out of alignment with our line of sight, ending its transits. "We think of the universe as resembling clockwork, where everything is regular, but that's not true," said Samuel Yee, a 51 Pegasi b Postdoctoral Fellow at UCLA and the paper's corresponding author. "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."

TOI-2535 b is not expected to transit again for 30 to 50 years, though the hidden neighbor may come into view sooner. The system offers clues about hot Jupiter formation. Current models suggest such planets form far from their stars where ice is abundant, then migrate inward. One pathway involves violent scattering into elliptical orbits; the other, gentler migration within a flat protoplanetary disk. The pronounced orbital tilt in TOI-2535 b's system suggests the slower migration scenario can still produce tilted orbits through later planetary interactions. "Because TOI-2535 b has a close neighbor, it probably migrated by slowly spiraling 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." The planet's properties were confirmed using the WIYN 3.5-meter telescope at Kitt Peak National Observatory in Arizona.