Astronomers have detected a planet-like object that orbits the sun at an extreme distance, raising the possibility that more undiscovered objects are just beyond the former planet of Pluto.
Until now, the only known object in this far-off region of the solar system known as the inner Oort cloud was a dwarf planet discovered a decade ago, called Sedna.
In a study published Wednesday in the journal Nature, researchers describe the new object, called 2012 VP113.
It’s still a mystery how both 2012 VP113 or Sedna got to the inner Oort cloud, but researchers now think there could be hundreds of thousands of objects in what was previously believed to be a “no-man’s-land” — we just haven’t detected them yet.
Where is the new object?
When scientists talk about the observable solar system, they are referring to a region that extends from the sun, beyond the last planet Neptune, to a disc-shaped region called the Kupier belt.
The Kupier belt extends from about 30 astronomical units (AU) from the sun — where one AU is equal to Earth’s mean distance from the sun, or about 93 million miles — to about 55 AU.
Just beyond the Kupier belt, at about 70 AU, lies the inner Oort Cloud. At an even farther distance, starting at around 5,000 AU, the Oort cloud becomes spherical and contains comets that take more than 200 years to orbit the sun, known as long-period comets.
2012 VP113 lies in a region between the Kupier belt and the spherical Oort cloud. Its closest approach to the sun is 80 AU, more distant than Sedna’s closest approach of 76 AU. 2012 VP113 is a little more than one-third the size of Sedna, estimated to be about 400 km (248 miles) across, whereas Sedna is about 1,000 km (621 miles) across.
Chad Trujillo of Gemini Observatory in Hawaii, and Scott Sheppard of the Carnegie Institution of Washington, detected 2012 VP113 using a ground-based telescope in Chile.
In a podcast, Trujillo said they don’t yet know what 2012 VP113 is made of, but the object is likely covered in ice since it’s so far away from the sun.
Studying 2012 VP113 will help scientists better understand how objects got to the inner Oort cloud in the first place.