Astronomers have discovered a far-out world circling the sun.

How far out? It’s so far out that the discoverers nicknamed it “Farout.” All they can see is a pinkish dot of light in the night sky, but that is enough to infer that they are looking at a 300-mile ice ball orbiting more than 11 billion miles from the sun — more than three times as far out as Pluto, and the farthest object ever observed within the solar system.

I t is the latest revelation in a distant region that was once expected to be empty, and studying its trajectory may help point to an as-yet-unseen ninth planet circling the sun far beyond Neptune.

On Monday, the International Astronomical Union’s Minor Planet Center announced the discovery and gave this object the designation 2018 VG18.

“Last month, we came across it moving very, very slow,” said Scott S. Sheppard of the Carnegie Institution for Science, one of the discoverers of VG18. “Immediately we knew it was an interesting object.”