Farout: Pink Dwarf Planet Is Farthest Object Ever Spotted in Solar System
Way past Pluto, the suspected Planet X creeps around the outer edges of our solar system. Nobody is sure whether this rumored ninth planet really exists, but astronomers have been hard at work searching for it in the dark fringes of our stellar neighborhood, as the video above shows. In the process, they’re turning up all sorts of mysterious new neighbors, including one that’s officially the farthest solar system object ever spotted: a mysterious pink dwarf nicknamed “Farout.”
“I actually uttered ‘farout’ when I first found this object, because I immediately noticed from its slow movement that it must be far out there,” Scott Sheppard, Ph.D., tells Inverse.
Sheppard, an outer solar system expert at Carnegie Institution for Science whose Wikipedia bio describes him as a “discoverer of numerous moons, comets and minor planets,” was part of the team that made the new discovery. “It is the slowest moving object I have ever seen and is really out there.”
That’s not an exaggeration While Earth is, by definition, 1 astronomical unit (AU) away from the Sun, Farout — real name 2018 VG18 — is 120 AU. Pluto, which used to be our benchmark for far-out planets (RIP), is 34 AU from the Sun.
The team first spotted this painfully slow-moving object in a series of photos snapped on November 10 by Japan’s Subaru 8-Meter telescope atop Mauna Kea in Hawaii. “We immediately knew it had to be very distant to have such slow motion across the sky,” said Sheppard. They reconfirmed its existence using the Magellan telescope in Chile in early December. Those observations revealed that Farout is spherical, has a diameter of about 500-600 km, and is pink.
“We really only know three things about 2018 VG18 right now,” says Sheppard, referring to its distance from the sun, its diameter, and its color. “Finally, we know its color is a pinkish hue, which is generally associated with ice that has been irradiated by the Sun’s rays over billions of years.”
Impressive as this rose-colored beauty’s discovery is, Sheppard can’t say he was too surprised. Since 2012, he and his colleagues have been hard at work performing what he calls the “largest and deepest search ever obtained for distant solar system objects.” Scanning both Northern and Southern hemispheres at all times of the year, they have managed to cover about 20 percent of the sky to date.
“So this wasn’t a serendipitous discovery as it is exactly what we are looking for, for Solar System objects that are way way out there, far beyond Pluto,” he says.
As they learn more about Farout’s orbit, they’ll be better able to deduce the whereabouts of Planet X, if it exists. The Planet X theory is an attempt to explain why the minor planets in the Kuiper Belt, at the very edges of our solar system, have such weird orbits. If it’s real and as massive as some scientists think, then its gravitational pull on its tiny neighbors would account for their bizarre patterns of movement around the Sun.
“The orbit is needed to see if it is consistent with the Planet X theory of a massive planet shepherding the smaller dwarf planets into similar types of orbits in the very distant solar system,” says Sheppard. “But 2018 VG18 was found on a similar part of the sky to the other known extreme objects, suggesting it could have a similar type of orbit, but only another year or so of observations will tell.”
Sheppard, who also discovered the spooky “Goblin” planet at the edges of the solar system around Hallowe’en, is sure that Farout, though unique and exciting, is far from the biggest discovery that’s yet to be made.
“How many more large distant objects are out there at the fringes of our Solar System?” he says. “That is what we hope to answer in the next few years as we continue our all sky survey for faint distant solar system objects.”