WASHINGTON (CN) — More than 100 times farther than the Earth is from the sun, a pink dwarf planet nicknamed Farout was recognized by astronomers Monday as the most-distant body ever observed in our solar system.
No solar system object has ever been detected at this distance, according to a statement from the Carnegie Institution of Washington.
Using the unit of measurement reserved for such lengths, where 1 astronomical unit is defined as the distance between the Earth and the sun, Farout is located at about 120 AUs. By comparison, Pluto is three and a half times closer at 34 astronomical units away. Eris, the previous record holder, is at about 96 AU.
The International Astronomical Union’s Minor Planet Center announced the discovery Monday, giving Farout the provisional designation 2018 VG18.
Credited with the discovery of Farout are Carnegie staff scientist Scott Sheppard, the University of Hawaii’s David Tholen and Northern Arizona University’s Chad Trujillo.
Carnegie noted that the same team announced the discovery in October of 2015 TG387, another distant solar system object that has been nicknamed “The Goblin” because of its Halloween-timed sighting.
Located at about 80 AU, The Goblin has an orbit consistent with an expected relationship to the unseen body that astronomers have dubbed Planet X, believed to be a supersize object on the very distant fringes of the solar system.
Sheppard, Tholen and Trujillo first proposed the existence of Planet X, which is sometimes also called Planet 9, in 2014 when they discovered 2012 VP113 at 84 AU.
Neither this 2014 discovery, nicknamed Biden, nor The Goblin get close enough to Neptune and Jupiter to have significant gravitational interactions with them.
Astronomers say this distance means the objects offer insight into what is happening in the outer reaches of the solar system.
Farout’s orbit meanwhile is still undetermined, so it is unclear whether Planet X affects it.
“2018 VG18 is much more distant and slower moving than any other observed solar system object, so it will take a few years to fully determine its orbit,” Sheppard said in a statement through Carnegie. “But it was found in a similar location on the sky to the other known extreme solar system objects, suggesting it might have the same type of orbit that most of them do. The orbital similarities shown by many of the known small, distant solar system bodies was the catalyst for our original assertion that there is a distant, massive planet at several hundred AU shepherding these smaller objects.”
Tholen noted that, apart from Farout’s extreme distance from the sun, researchers have thus far been able to determine only its approximate diameter and its color.
“Because 2018 VG18 is so distant, it orbits very slowly, likely taking more than 1,000 years to take one trip around the sun,” Tholen said, as quoted by Carnegie.
The astronomers first located Farout in images taken at the Japanese Subaru 8-meter telescope located atop Mauna Kea in Hawaii on Nov. 10, 2018.
It takes multiple nights of observation to accurately determine an object’s distance, however, and the scientists spotted 2018 VG18 again earlier this month with the Magellan telescope at Carnegie’s Las Campanas Observatory in Chile.
Graduate student Will Oldroyd of Northern Arizona University is said to have helped with the recovery observations.
Using the Magellan telescope, the team monitored Farout to secure its path across the sky, while also ironing out its brightness, color and other physical properties.
Farout’s brightness suggests that it is about 500 km in diameter, according to the Carnegie report, which explains that this size likely makes the object “spherical in shape and a dwarf planet.”
“It has a pinkish hue, a color generally associated with ice-rich objects,” Carnegie’s report continues.