Strange interstellar object could be a shard from a dead planet

‘Oumuamua, the first object known to have come from beyond the solar system, might have gotten its oblong shape when a planet was shredded by a faraway star.

AN UNUSUAL VISITOR cruised through the solar system in late 2017—a small, rocky object that did not hail from Earth’s neighborhood, but was born in a star system far, far away.

The interstellar visitor—named ‘Oumuamua by the team that discovered it, which roughly translates from Hawaiian as “a messenger from afar arriving first”—provided more than a few puzzles. First spotted by the Pan-STARRS project at the Haleakalā Observatory in Maui, the tumbling object accelerated in ways that could not be explained by gravity alone. And based on the light it reflected, ‘Oumuamua appeared to be an elongated, cigar-shaped object—a shape unlike anything seen in our own solar system.

New computer simulations reveal a possible origin story for this strange interstellar object: A world was ripped to pieces by its home star, leaving behind a wake of long, thin fragments. Some of these fragments would have been launched into interstellar space, and millions—perhaps billions—of years later, ‘Oumuamua reached our solar system. The simulations point to three possible types of home systems for ‘Oumuamua, and the work explains both the elongated shape and curious motion of the interstellar visitor.

“’Oumuamua provides a lot of problems to explain its origin,” says Yun Zhang, a researcher at the Côte d’Azur Observatory in France and lead author of a study on the simulations published today in Nature Astronomy. “Before our study, no solution can produce such an elongated shape.”