Hot Jupiter TOI-1355 b's tilting orbit will make it disappear from view by 2033

By the Everything Space news desk · 30 Sep 2026 · written from the sources below

Image: Universe Today

The distant gas giant's shifting eccentric orbit offers a limited-time chance to study how hot Jupiters evolve before its transits become undetectable from Earth.

Astronomers have identified a hot Jupiter, TOI-1355 b, whose orbital tilt is changing so quickly that it will stop transiting its star as seen from Earth by 2033, cutting off a key method for studying the planet.

TOI-1355 b lies about 805 light-years away, carries roughly 5.84 times Jupiter's mass and 1.42 times its radius, and completes an orbit around its star in just over two days. Unlike Earth's nearly circular path, its orbit is notably eccentric, a trait researchers say may reveal a turbulent orbital history shaped by gravitational interactions with other bodies in its system.

Using transit data from NASA's TESS spacecraft along with ground-based observations from Kyoto University's Okayama Observatory, researchers found that the timing of the planet's secondary eclipse did not match what would be expected from a circular orbit, prompting closer study. That analysis revealed the planet's orbital tilt is gradually shifting, and current trends suggest that within less than a decade it will transit its star at a different position, making it invisible to telescopes on Earth.

The study's lead author noted that while planet searches around sun-like or cooler stars are well developed, surveys around hotter stars remain less advanced, which is part of why this discovery stood out as unusual.

Hot Jupiters have long puzzled astronomers because their extreme proximity to their stars suggests they likely formed farther away and migrated inward over time, a process thought to also apply to Jupiter in our own solar system. Studying eccentric hot Jupiters like TOI-1355 b before they vanish from observation could offer clues about how such migrations and orbital shifts unfold across other planetary systems.

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