System has four stars and a planet-forming disk oriented vertically

Enlarge / Artist's conception of the B binary in the quad-star system HD 98000. (credit: University of Warwick/Mark Garlick.)
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.
Read 12 remaining paragraphs | Comments