The object under the temporary nickname “Farfarout” has the official designation 2018 AG37 , although, presumably it will receive an official name after experts have better determined its orbit in the next few years , as happened with cosmic bodies like Sedna (which it was discovered in 2033), Orcus (in 2004) or Varuna (in 2000).
This planetoid (a small celestial body that orbits the Sun) recently confirmed by astronomers at the University of Hawaii has a very elongated orbit that takes it to 175 Astronomical Units (AU) at its most distant point, and within the orbit of Neptune, at around 27 AU, when it is close to the Sun. Its mean distance from the Sun is 132 astronomical units, that is, four times farther from Pluto and 132 times farther from the Sun than Earth. (And it is that, in comparison, Pluto is only 39 AU from the Sun). It is the most distant object ever observed in our solar system.
It is the most distant ‘trans-Neptunian’ object known ; in other words, it is farther away than any minor planet or dwarf planet in the solar system with an orbit beyond Neptune.
“A single Farfarout orbit around the sun takes a millennium,” said David Tholen, a member of the discovery team and an astronomer at the University of Hawaii. “Due to this long orbital period, it moves very slowly across the sky, requiring several years of observations to accurately determine its trajectory.”
As a curiosity, in its orbit closest to the Sun it plunges just 24 astronomical units from our star , closer to the Sun than the orbits of Pluto and Neptune. The difference with its furthest point is abysmal (175 AU).
Experts estimate that the planetoid is 400 kilometers wide , which puts it in the lowest possible range for a dwarf planet (like Pluto) if it is rich in ice. The object was first detected in 2018 , hence its name, but it took two more years for its official confirmation using nine observations that showed the planetoid’s motion and provided clues about its orbit. As a result, the planetoid has just received an official designation from the Minor Planet Center in Cambridge, Massachusetts, which identifies, designates, and calculates the orbits of small objects in the solar system.
Accidental discovery
Farfarout (remember that it will get a catchier name in the future) was accidentally discovered while scientists were searching for Planet Nine, the hypothetical member of our solar system and potentially the ninth official planet after Neptune.
According to the researchers, more such objects are likely to appear as technology for detecting faint, distant rocks improves and astronomers continue to search for the elusive Planet Nine.
“Only with the advances in recent years of large digital cameras in very large telescopes has it been possible to efficiently discover very distant objects such as Farfarout,” the experts add. “Farfarout is just the tip of the iceberg of solar system objects in the farthest part of our solar system.”
Referencia: S.S. Sheppard et al. 2021. 2018 AG37. MPEC 2021-C187 Northern Arizona University
