First Visitor From Outside Our Solar System Has a Name and an Origin

An artist's representation of an asteroid (not ‘Oumuamua). NASA

Less than a month after spotting the first ever confirmed object from another solar system visiting Earth, astronomers haven't just given it a name, 1I/'Oumuamua—they even think they know where it came from. That's according to a new article posted on the physics pre-print server arxiv and submitted for publication to the journal Research Notes of the American Astronomical Society.

Astronomers were first struck early in their observations of the object, which at the time they thought was a comet, by its extraordinarily weird path. Most comets travel more or less in the plane of space that contains Earth, our sun, and our neighboring planets. Not this one: It swooped in from above that plane, then twirled around the sun and flew up again, tracing out a dramatic arc that will never bring it back to our solar system.

And as they got a better look at the mystery visitor, the plot thickened: They realized it wasn't a comet at all, since it lacks a comet's trademark fuzzy bubble surrounding its core. That meant it must actually be an asteroid, a hunk of space rock from a distant solar system.

Since then, the astronomical community has come together to give it a name—and that alone required some thinking on their feet, since no one had ever bothered to design a naming scheme for a phenomenon we'd never seen. They settled on 1I/'Oumuamua, representing the first (1) interstellar (I) object. 'Oumuamua was chosen by the team that first spotted it, based at the Pan-STARRS telescope in Hawaii. The name memorializes its status and is inspired by the Hawaiian words for being first to reach out.

And now there's even more exciting news: Astronomers think they know where 'Oumuamua came from. They figured that out by tracing its path backward along the observations that have been made so far and accounting for the wiggles that would have been caused by the gravitational tug of the large objects it flew past.

Read more: Mysterious Visitor From Another Solar System Flew by Earth, Leaving Astronomers Baffled

That led a trio of scientists to consider a neighborhood near the Carina and Columba constellations in the southern sky. There, somewhere in a cluster of stars, 'Oumuamua was born in a disk of pre-planetary dust, close enough to its star to be more rock than ice—until 40 million years ago. Then, something dramatic (they think a nearby planet had something to do with it) abruptly booted it out of the area, sending it on its odyssey to Earth.

'Oumuamua may be the first, but it won't be the last, and the authors of the new paper know it. They conclude the article: "We predict that future interlopers could radiants similar to ['Oumuamua]: Watch this space."