Hoag’s Object: Galactic Tutu Came Naturally
A galactic oddball may have spun itself into its strange bull’s-eye shape, report astronomers probing the origins of Hoag’s Object.
The galaxy, made up of a golden sphere of stars in the middle of a much bigger star-studded hula hoop, had once been thought to have formed as the result of a cosmic smashup.
Now, using both ground- and space-based observations, Israeli and Russian astronomers propose that the object formed that way on its own. The golden core formed first, at least 10 billion years ago. Soon after, the core skirted itself with a disk of hydrogen gas that it pulled from surrounding material. The disk’s spiral pattern could be caused by rotation of the core, if the central cluster isn’t quite spherical.
That setup would also explain the ongoing star formation that dots the ring with young, massive stars, the team reports in an upcoming Monthly Notices of the Royal Astronomical Society.