Astronomers Found a Planet Nine Candidate—But It’s in the Wrong Place

A squad of astronomers says it has identified a single, slow-moving infrared entity that checks each the close boxes for it being the long-theorized ninth satellite lurking beyond Neptune.

The hunt for Planet Nine—the star system’s ghostly gravitational troll—is longstanding, and is based connected the peculiar clustering of rocky bodies successful the Kuiper Belt beyond the orbit of Neptune. This clustering suggests the beingness of immoderate faint, monolithic object. But the squad down the caller survey took a caller attack to the search: investigating infrared information that’s been collecting particulate for decades.

The research, posted this period to the preprint server arXiv and acceptable to people successful the Proceedings of the Astronomical Society of Australia, comes from a radical of scientists successful Taiwan, Japan, and Australia. The radical pored implicit archival information from 2 infrared abstraction telescopes, NASA’s IRAS mission from 1983, and Japan’s AKARI satellite from 2006 to 2007. Their goal: find immoderate entity that’s cold, faint, and dilatory capable to beryllium Planet Nine.

The hunt builds connected a mentation that made headlines successful 2016, erstwhile Caltech astronomers Mike Brown and Konstantin Batygin proposed a massive, hidden planet based connected the Kuiper Belt objects’ clustering patterns. In a 2021 update, the duo refined the theory, estimating Planet Nine to beryllium conscionable implicit six times Earth’s mass, with an orbit of 7,400 years—close capable to detect, possibly, with the upcoming Vera Rubin Observatory.

Enter the infrared search. Astronomer Terry Long Phan from National Tsing Hua University successful Taiwan and his colleagues utilized the 23-year spread betwixt IRAS and AKARI to look for highly distant objects that moved conscionable a small spot betwixt snapshots. After applying filters for stars, galaxies, and different noise, they were near with 1 candidate. It doesn’t lucifer immoderate known entity and appears to person moved conscionable capable to plausibly beryllium a missing planet.

“The insubstantial is simply a nicely done analysis, but it is missing 1 happening that I would person hoped to person seen: a treatment of the probability that the detections are simply sound oregon immoderate astrophysical transient that hap to beryllium adjacent unneurotic implicit a 23-year period,” Brown told Gizmodo successful an email.

The object’s faint signature and highly dilatory question suggest a satellite acold beyond the orbit posited by Brown and Batygin, arsenic good arsenic different Planet Nine estimates. It’s a caller pb connected the phantom object, albeit 1 starring successful an wholly antithetic direction.

“The different absorbing constituent is that the orbit of this entity is not accordant with our predictions for Planet Nine,” Brown added. “That doesn’t mean it is not real, conscionable that if it IS existent it is not the predicted Planet Nine, it is thing unpredicted.”

“My suspicion is that it is simply noise, but it volition beryllium amusive to find out,” helium said.

So astronomers stay cautious. Two information points decades isolated aren’t capable to pin down an orbit, and the root could inactive beryllium an unrelated inheritance entity oregon a information artifact. Still, the authors suggest the entity is agleam capable to beryllium re-detected utilizing ground-based telescopes, specified arsenic the Dark Energy Camera (DECam) successful Chile.

The caller probe besides undercuts immoderate of the much fringe Planet Nine theories—like the thought that it’s a primordial achromatic hole—since the evident entity is emitting airy successful the infrared. If follow-up observations corroborate a planetary object, that would beryllium a large triumph for the team’s approach—and validate the longstanding conception of a hidden satellite successful our system, albeit a antithetic 1 than antecedently postulated.

For now, Planet Nine remains theoretical. But this could beryllium the archetypal existent glimpse of thing real retired there—a faint constituent of airy drifting done the dark, waiting for our exertion and ingenuity to drawback it successful the enactment of being.