Astronomers led by researchers at the University of California, Los Angeles, have reported what they describe as the first known "vanishing planet". The gas giant TOI-2535 b, about 1,000 light-years from Earth, gradually stopped being observable to watchers on Earth. The planet was not destroyed or ejected from its system. It was hidden by gravitational effects, the researchers say. The findings were published in The Astrophysical Journal Letters.
TOI-2535 b is a hot Jupiter, a gas giant orbiting very close to its star. A single orbit takes only about 8.25 Earth days. That proximity makes it possible to detect transits, the brief dimming of a star's light when a planet passes across its disk. NASA's TESS telescope tracked these transits from April 2019 to March 2026.
Over those seven years the transits changed in ways that puzzled the team. Their timing drifted from the expected schedule by up to six hours. Each year the transits grew shorter and shallower. By 2026 the planet had stopped transiting in a form that could be observed from Earth.
The researchers attribute the disappearance to a second massive planet in a tilted orbit located nearby. The mutual gravity between the two bodies causes the orbit of TOI-2535 b to wobble. That wobble shifted the planet's path out of the line of sight of observers. The team calls it the most extreme example of planet interaction on record.
The next transit is predicted to occur in roughly 30 to 50 years. The hidden companion, however, could come into view earlier. The exact masses and orbit of that companion remain uncertain, and the researchers have not confirmed them.
The discovery challenges standard models of how hot Jupiters form and migrate. Two main scenarios have been proposed. In the first, violent scattering throws planets onto new orbits. In the second, gentle drift driven by the disk of gas and dust around a young star slowly moves them inward. The data, according to the authors, favor a rarer scenario of slow forced drift. That scenario is not yet confirmed.