The most distant known object in the solar system has now been confirmed. FarFarOut, a large piece of rock found at a staggering 132 astronomical units from the sun in 2018, has been studied and characterized, and we now know much more about it and its orbit.
It is about 400 kilometers (250 miles) wide, which is at the bottom of the dwarf planet’s scale, and early observations suggest it has an average orbital distance of 101 astronomical units – that’s 101 times the distance between Earth and the sun.
Since Pluto has an average orbital distance of about 39 astronomical units, FarFarOut is indeed very, well, far away. It has been provisionally designated 2018 AG37, and his proper name, in accordance with the guidelines of the International Astronomical Union, is still pending.
However, that orbit is not an even circle around the sun, but a really skewed oval. After careful observation, scientists have calculated its orbit; FarFarOut swings up to 175 astronomical units, coming in as close as 27 astronomical units, within Neptune’s orbit.
(Roberto Molar Candanosa, Scott S. Sheppard / CIS and Brooks Bays / UH)
This means that the object could help us better understand the planets of the outer solar system.
FarFarOut was likely thrown into the outer solar system by getting too close to Neptune in the distant past, said astronomer Chad Trujillo of Northern Arizona University. “FarFarOut will likely interact with Neptune again in the future, as their orbits still intersect.”
The object’s nickname originated from the discovery of a previously distant object in 2018.
Artist’s impression of FarFarOut. (NOIRLab / NSF / AURA / J. Da Silva)
The dwarf planet Farout has an average orbital distance of 124 astronomical units and is named after an exclamation by astronomer Scott Sheppard of the Carnegie Institution for Science. When he and his team discovered an even further object, progress was evident.
FarFarOut is still very mysterious, however. Because it is so far away, it is extremely faint and has only been observed nine times over the course of two years. The team deduced the size based on the clarity, but we don’t know much else; it could be a very large irregular Kuiper belt object, or it could meet the criteria to be classified as a dwarf planet.
Discovery images from FarFarOut obtained July 2018. (Scott S. Sheppard / Carnegie Institution for Science)
The astronomers are also not entirely sure of its orbital period. They think it may be just 800 years old (Pluto’s is 248), but there’s enough wiggle room to take more than twice the time, or possibly move at a much faster pace.
So, many more observations will have to be made to understand it better.
“It takes a millennium for FarFarOut to go around the sun,” said astronomer David Tholen of the University of Hawai’i in Mānoa. “This makes it move very slowly through the sky, requiring several years of observations to accurately determine its trajectory.”
Sheppard, Tholen and Trujillo are working to study the outer solar system in hopes of getting a glimpse of Planet Nine, a hypothetical object believed to be responsible for the strange movement of clusters of objects in the outer regions beyond Pluto.
There are other explanations for these jobs, but the job has an excellent side benefit. The team has discovered a number of objects that we did not know. There is of course Farout and FarFarOut. There is also a dwarf planet nicknamed The Goblin, discovered at a distance of 80 astronomical units.
There is even an object called 2014 FE72, whose orbit takes it beyond 3,000 astronomical units, the only known object of its kind to orbit completely outside Neptune’s. (It’s currently a lot closer after getting close to the sun in 1965.)
It’s not just the outer solar system, either. The researchers have discovered 12 previously unknown moons orbiting Jupiter and 20 moons orbiting Saturn.
So if there is planet nine, it probably seems to be the people who will find it. But in the process, they reveal a great deal about the outer solar system.
“The discovery of FarFarOut shows our increasing ability to map the outer solar system and observe further and further towards the edges of our solar system,” said Sheppard.
“Only with the advancement in recent years of large digital cameras on very large telescopes has it become possible to efficiently discover very distant objects such as FarFarOut. Although some of these distant objects are quite large – as big as dwarf planets – they are. they are. very dim because of their extreme distances from the sun. FarFarOut is just the tip of the iceberg of objects in the very distant solar system. “