A Search for Planet Nine with IRAS and AKARI Data - publication
2025-04-24
Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart, if the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.
Phan and Goto used sky surveys from two infrared space telescopes launched 23 years apart: the Infrared Astronomy Satellite (IRAS), a NASA-Netherlands-U.K. satellite launched in 1983; and AKARI, a Japanese satellite launched in 2006. Because of Planet Nine’s long orbit, the researchers hypothesized that the time gap between the two data sets would be enough to see the potential planet move incrementally across the night sky. From an initial catalog of about 2 million objects within the IRAS and AKARI data sets, the researchers whittled down to pairs of dots of light whose spacing could be explained by a moving planet with a Planet Nine–like mass and distance. Then, they removed known sources such as stars, sources that didn’t move over time, and sources with too much noise, such as those near the bright galactic center. When 13 pairs remained, they checked each by eye. Only one candidate pair survived the scrutiny. The two dots had matching colors and brightnesses—a sign they were the same object.
Links:
Astronomers searching for Planet Nine find possible hints of different planet
Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

Very-wide-orbit planets from dynamical instabilities during the stellar birth cluster phase - publication
2025-05-27
There could be a ninth planet in our Solar System after all and it’s not Pluto; instead, it’s the theoretical Planet X, also called Planet Nine, a wide-orbit planet that would circle the Sun from far beyond Neptune and Pluto.
Planet X has been hypothesized for years, but how such a planet could have appeared in the outer Solar System has long stumped scientists. The study in Nature Astronomy ‘Very-wide-orbit planets from dynamical instabilities during the stellar birth cluster phase’ reveals a novel theory, however. The research suggests that wide-orbit planets (such as Planet X) arise in the early evolution of their planetary systems, when these systems are still inside their stars’ crowded birth clusters. In these tight, chaotic settings, stars and their planets are fighting for space, and sometimes planets are sent flying.
Links:
‘Pinballs in a cosmic arcade’: New study suggests how wide-orbit planets form, supporting existence of Planet Nine
Chaos in Our Solar System Could’ve Caused Planet X’s Theoretically Wide Orbit
