Rogue Planet Gave Itself Away with Warped Light express
The lone planet KMT-2024-BLG-0816, one of many free-floating planets, was discovered when its gravity acted like a magnifying glass for a few hours. Passing in front of a distant star, the invisible body warped space like a glass marble, and boosted the background light. Thanks to a rare coincidence, the planet passed so close to the line of sight that telescopes could observe how the brightness of different parts of the stellar disk changed — the lens slid across its surface.
A faint stray light added to the mystery: it doesn't look like starlight, but could be the ghost of its former host. If confirmed, for the first time a lone planet will be seen together with its parent star — albeit separated by trillions of kilometers. Subsequent brightness measurements in different colors will test this hypothesis.
Original abstract
as written by the authors arXiv:2601.00325v1
We present the discovery of a free-floating planet microlensing event KMT-2024-BLG-0816. The event shows finite-source effect, significant blending light, and no microlensing signal from a putative planet host. Among the free-floating planet events with finite source effects, this is the only event with unresolved blending light. We discuss how follow-up observations can be used to determine whether the blending light originates from a putative planet host.
Gravitational lensing was predicted by Einstein back in 1936, but he thought it impossible to detect.
In science fiction, rogue planets are icy worlds holding secrets of ancient civilizations, like in Asimov's novel 'Nemesis'.