The Mystery of the “Disappearing” Exoplanet

Astronomers have solved the strange case of TOI-2535 b, a hot-Jupiter exoplanet about 1,000 light-years from Earth that appeared to vanish while scientists were observing it. NASA’s TESS spacecraft had monitored the planet transiting, or passing in front of, its star. But over several years, the timing, duration, and depth of those transits gradually changed until the planet stopped transiting altogether. The planet hadn’t actually disappeared. Instead, astronomers concluded that the gravity of another, unseen planet in the system was changing the orientation of TOI-2535 b’s orbit.

Artist’s illustration of a hot Jupiter type of exoplanet.
Maybe this looks something like TOI-2535 b, a hot Jupiter — 1,000 light-years away — that “disappeared.”
Image via ESO/ M. Kornmesser.

The two planets appear to gravitationally tug on one another, causing their tilted orbits to wobble somewhat like spinning tops. Eventually, TOI-2535 b’s orbit shifted enough that the planet no longer passes directly between its star and Earth, making its transits invisible to us. The interaction is unusually strong and may also provide clues about how hot Jupiters migrate into extremely close orbits around their stars. TOI-2535 b completes an orbit in just 8.25 days, but astronomers estimate that its orbital alignment may not bring its transits back into view for another 30 to 50 years.

For the complete story see EarthSky.