A newly discovered object is the most-distant body ever observed in the solar system — and the first object ever found orbiting at more than 100 times the distance from Earth to the sun.
The discovery team nicknamed the object "Farout,"
and its provisional designation from the International Astronomical Union is
2018 VG18. Preliminary research suggests it's a round, pinkish dwarf planet.
The same team spotted a faraway dwarf planet nicknamed nicknamed “The Goblin”
in October.
"All that we currently know about 2018 VG18 is its
extreme distance from the sun, its approximate diameter, and its color,"
David Tholen, a researcher at the University of Hawaii and part of the
discovery team, said in a statemen. "Because 2018 VG18 is so distant,
it orbits very slowly, likely taking more than 1,000 years to take one trip
around the Sun."
Farout is 120 astronomical units (AU) from the sun —
one AU is the distance between Earth and the sun, which is about 93 million
miles (150 million kilometers). The object is more than 3.5 times the current
distance between Pluto and the sun (34 AU), and it outpaces the previous
farthest-known solar system object, the dwarf planet Eris, which is currently
about 96 AU from the sun. NASA's Voyager 2 spacecraft recently entered
interstellar space at about 120 A.U., leaving the sun's "sphere of
influence" called the heliopause, where bodies experience the solar wind.
To be clear: The record Farout now holds is for the
most-distant solar system body ever observed. That doesn't mean no other
objects gets farther away from the sun than 120 AU. In fact, we know some that
do. The dwarf planet Sedna gets more than 900 AU away on its highly elliptical
orbit, for example, and there are probably trillions of comets in the Oort
Cloud, which lies between about 5,000 AU and 100,000 AU from the sun.
Farout was first spotted using the Subaru 8-meter telescope
in Hawaii in November, and then a follow-up measurement in early December by
the Magellan telescope in Chile confirmed its existence. According to those
observations, the object is likely about 500 km across, which would mean it's
spherical and a dwarf planet. Its pinkish color suggests it's an ice-rich body,
according to the statement.
"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," Scott Sheppard, a researcher at the Carnegie
Institution for Science in Washington, D.C., and member of the discovery team,
said in the statement. "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."
"This discovery is truly an international achievement
in research using telescopes located in Hawaii and Chile, operated by Japan, as
well as a consortium of research institutions and universities in the United
States," Chad Trujillo, a researcher at Northern Arizona University and
the third member of the discovery team, said in the statement. "With new
wide-field digital cameras on some of the world's largest telescopes, we are
finally exploring our Solar System's fringes, far beyond Pluto."
Reference:
https://www.space.com/42755-farout-farthest-solar-system-object-discovery.html?utm_source=notification
