Flagstaff Astronomer Discovers Rare 'Inner Oort Cloud' Object

Oct 3, 2018

A Flagstaff astronomer turned up a rare object at the edge of the solar system that strengthens the case for an undiscovered massive planet. KNAU’s Melissa Sevigny reports.

Illustration of hypothetical Planet X
Credit Roberto Molar Candanosa and Scott Sheppard, courtesy of Carnegie Instituion for Science

Chad Trujillo of Northern Arizona University says the new object is one of only three known to exist in a distant region of space called the inner Oort cloud. The object is two and a half times further from the Sun than Pluto. Its orbit fits with computer models that point to an unknown planet.

"That’s what’s interesting to me," Trujillo says. "It’s not proof but as we find more objects, if they all fit this picture, that is suggestive that there’s a planet or something out there that we don’t understand."

Trujillo and a colleague, Scott Sheppard of Carnegie Instituion of Science, first proposed the hypothetical planet four years ago. They’re searching for it with telescopes in Hawaii, Chile, and Arizona. The inner Oort cloud object turned up in their deep-sky survey. Trujillo says it’s unknown how these objects formed. So the discovery could help improve models of the early solar system.