Among some astronomers, there is a growing suspicion that our solar system’s distant reaches conceal a large, ninth planet that we have not yet seen. New findings about a small ice world far beyond Pluto buttress this idea.

On Monday, astronomers led by Scott S. Sheppard of the Carnegie Institution for Science in Washington revealed the orbital details of the world, which they have nicknamed the Goblin. Dr. Sheppard and his colleagues first spotted the world, which for now carries the official designation of 2015 TG387 as part of a systematic search three years ago for new worlds in the outer system, including the hypothesized Planet Nine. But only with additional observations did they realize how far out TG387 really is.

“It took us three years to figure out that it has an interesting orbit,” Dr. Sheppard said.

The astronomers have submitted a paper describing the discovery to The Astronomical Journal.

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The world, estimated to have a width of a couple of hundred miles, is currently about 7.4 billion miles from the sun, or about 2.5 times farther away than Pluto. But that is near to the closest it ever gets to the sun.