Astronomers Puzzled After Watching Entire Planet Wink Out of Sight

An international group of scientists observed a gas giant named TOI-2535 b unexpectedly disappearing from the sky, baffling astronomers. The exoplanet, about 1,000 light-years away, is a "hot Jupiter" that orbits its star very closely, completing a rotation in just over eight days. Its surface is extremely hot, which led to NASA's Transiting Exoplanet Survey Satellite tracking the planet multiple times between 2019 and 2026.

However, they noticed something peculiar: the planet's brightness dipped every time it passed in front of its star, and its appearance often occurred too early or too late. In the latest issue of the Astrophysical Journal Letters journal, the team explained their findings. They believe that a yet-to-be-discovered neighboring planet is influencing TOI-2535 b's orbit, causing it to appear as if the planet vanishes from view due to the two planets' orbits wobbling each other like a top.

University of California, Los Angeles postdoctoral fellow and lead author Samuel Yee explained the unusual situation, stating that in a typical universe, one might expect predictable, clockwork-like orbits. Yet, when multiple planets are present, they can affect each other's orbits, leading to the extreme case they observed. This specific case, with its strongly interacting planets, is the most extreme they've encountered.

The discovery may provide insights into the formation and migration of hot Jupiters, which are usually not accompanied by other planets close enough to disrupt their orbits. One possibility is that a near-collision with another celestial object caused the exoplanet to enter an elliptical orbit, while another is that violent interactions within the protoplanetary disk led to their tilted orbits.

Yee concluded that TOI-2535 b's presence of a close neighbor likely led to its slow migration rather than being flung in. He added that this unusual formation channel might be rare but intriguing.