An exoplanet about 1,000 light-years from Earth gradually disappeared from the view of the TESS space telescope. It is TOI-2535 b – a “hot Jupiter” gas giant that orbits its star every 8.236 days.
The planet was not directly visible. Astronomers detected it through transits – the moments when it passes in front of its star and temporarily reduces its brightness. TESS observed the system between April 2019 and March 2026, but toward the end of that period, the signal disappeared.
Observations showed that the change was not sudden. The transits of TOI-2535 b began occurring up to six hours earlier or later than expected. At the same time, the transits became shorter and weaker, until in 2026 the telescope could no longer detect the planet in front of its star.
The planet has not physically disappeared
According to the team from the University of California, Los Angeles, the most likely explanation is the gravitational influence of another planet that has not yet been observed. Its orbit is likely inclined relative to that of TOI-2535 b. The mutual attraction changes the orientation of both orbits and gradually moves the gas giant outside the line along which we observe it from Earth.
“The planet’s orbit is tilting so quickly that its transit disappeared while we were observing it,” says Samuel Yi, the study’s lead author and a postdoctoral researcher at UCLA. According to him, this is the most extreme known example of a strong interaction between two planets.
The scientific model indicates that the invisible companion is probably a planet with at least the mass of Saturn and may be in or near orbital resonance with TOI-2535 b. This means that the orbital periods of the two bodies are linked in a way that amplifies their gravitational influence on each other.
The next transit will occur decades from now
Researchers estimate that TOI-2535 b may pass in front of its star again in about 30–50 years. Its unobserved companion could become visible sooner if its orbit brings it into a suitable position relative to Earth.
The case also has implications for understanding “hot Jupiters” – gas giants located unusually close to their stars. According to scientists, the interaction between the planets suggests that TOI-2535 b may have slowly migrated inward toward the star together with the other body, rather than being pushed into a close orbit after a single strong encounter.
The results were published in The Astrophysical Journal Letters.
Sources: obozrevatel.com, phys.org, space.com