So many unexplored secrets still lie at the outskirts of our solar system, where a potential candidate for a new dwarf planet lies. Although space beyond Neptune was thought to be mostly devoid of large objects, researchers are beginning to rethink this assumption after coming across an extraordinary trans-Neptunian object, called 2017 OF201.
According to a recently published arXiv pre-print, 2017 OF201 could soon join the ranks of Pluto and other dwarf planets in the solar system. The behavior of its extremely large orbit has piqued the interest of astronomers, who now believe there may be plenty more objects just like it drifting through this remote part of space.
Where are Dwarf Planets Located?
The Kuiper Belt, a region of the solar system past Neptune’s orbit, is likely home to hundreds of thousands — if not millions — of icy objects that vary in shape and size. Over 2,000 trans-Neptunian objects (TNO) have been observed here, but scientists believe that this figure doesn’t even scratch the surface of this area’s extraterrestrial riches.
The most famous resident of the Kuiper Belt, without a doubt, is Pluto. Other dwarf planets have also been found in the area, such as Eris, Haumea, and Makemake. But why do Pluto and its fellow dwarf planets not enjoy the same status as the solar system’s eight regular planets?
To officially be considered a planet, an object must follow three rules set by the International Astronomical Union in 2006: It must orbit a host star (like the Sun), be mostly round, and be large enough to clear away objects of a similar size near its orbit (in other words, it has to be “gravitationally dominant”). Dwarf planets like Pluto follow the first two rules, but they cannot “clear the neighborhood” near their orbits.
Read More: Pluto May Have Formed From the Newly Discovered Kiss and Capture Mechanism
The Extreme Orbit of 2017 OF201
Scientists have been eager to uncover more TNOs in the Kuiper Belt, which is what led to the discovery of 2017 OF201. The object was identified based on bright spots in an astronomical image database from the Victor M. Blanco Telescope and Canada-France-Hawaii Telescope. Assessing exposures over seven years, the researchers were led to 2017 OF201, which is one of the most distant visible objects in our solar system at this point.
The most significant aspect of 2017 OF201 appears to be its extreme orbit.
“The object’s aphelion — the farthest point on the orbit from the Sun — is more than 1600 times that of the Earth’s orbit,” said author Sihao Cheng of the Institute for Advanced Study in Princeton, NJ, in a press statement. “Meanwhile, its perihelion — the closest point on its orbit to the Sun — is 44.5 times that of the Earth’s orbit, similar to Pluto's orbit.”
The researchers estimate the object’s diameter to be 700 km [about 435 miles], “which would make it the second largest known object in a wide orbit," according to the statement. Pluto’s diameter, for reference, is 2,377 km [about 1477 miles].
Mysteries of the Kuiper Belt
The object’s orbit, which takes around 25,000 years to complete, may be the result of an encounter with a larger planet that sent it far into space. The object also doesn’t show signs of clustering in a specific orientation, something commonly observed with other TNOs.
Clustering has often been referenced as indirect evidence for the existence of a hypothetical ninth planet in the outer solar system (called Planet Nine or Planet X). But since 2017 OF201 doesn’t follow the same pattern as other TNOs, it may stand against this hypothesis.
The researchers hope to gather more details on 2017 OF201 in future observations. The excitement doesn't stop at this object, since its discovery hints at an abundance of similar objects in the Kuiper Belt, still waiting to be observed.
“2017 OF201 spends only 1 percent of its orbital time close enough to us to be detectable. The presence of this single object suggests that there could be another hundred or so other objects with similar orbit and size; they are just too far away to be detectable now,” said Cheng in a press release. “Even though advances in telescopes have enabled us to explore distant parts of the universe, there is still a great deal to discover about our own solar system.”
Read More: Another Earth Could Orbit In The Distant Reaches Of The Solar System, Say Astronomers
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Earth and Planetary Astrophysics. Discovery of a dwarf planet candidate in an extremely wide orbit: 2017 OF201
NASA. Kuiper Belt Facts
NASA. Dwarf Planets
Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
