Models and observations indicate that both stars and planets form as a cloud of material collapses into a disk. If the process proceeds in an orderly manner, then the planets will all form from the same disk and thus orbit in the same plane. And—because material from the same disk will fall into the star, bringing its momentum with it—the star will rotate with its equator along the same plane. That should lead to a tidy system with the equator of the star lined up with the plane of any planets orbiting it.
Except when it doesn’t. Anything that upsets the even inflow of material—from clumping in disk to a passing star—can upset this process. We’ve seen the results: planet-forming disks and planetary orbits that don’t line up with a star’s equator.
Now, researchers are reporting a complex, four-star system where a planet-forming disk is lined up perpendicular to the stars, so that it orbits over their poles.