Astronomers found a giant ring of dust spinning around two stars in the completely wrong direction.
March 23, 2026
Original Paper
The Arc in the DX Cha Circumbinary System: Evidence For a Retrograde Circumbinary Disk
arXiv · 2603.19983
The Takeaway
In most solar systems, everything spins in the same direction because they formed from the same swirling cloud. Finding a 'retrograde' disk is like seeing a highway where one lane is driving backward, and it explains how dust can survive much closer to the stars than physics usually allows.
From the abstract
Observations of the binary system DX Cha (HD 104237) reveal a compact, asymmetric ring structure with a radius of 0.43\,au. This ring is just outside the binary orbit, which has semi-major axis $a_{\rm b} = 0.22$\,au and eccentricity $e_{\rm b} = 0.665$; placing the ring at $\approx 1.2$ times the binary apocenter distance. The inner regions of circumbinary disks, $\approx 2-3\,a_{\rm b}$, are typically evacuated by strong gravitational torques from the binary, resulting in a deep gap between th