That bright star in the Southern Cross? It’s not one star. It’s actually a crazy family of seven stars all huddling together.
arXiv · March 13, 2026 · 2603.11194
Why it matters
Using high-precision interferometry, astronomers 'upgraded' this famous star system from five to seven members. Finding that these stars orbit in completely different, misaligned planes suggests a chaotic and violent formation history for one of our nearest massive neighbors.
From the abstract
Alpha Crucis is the closest very high multiplicity massive star to the Sun. At its heart is the $4" \leftrightarrow 430 \text{ au}$ binary $\alpha^1$ (A) + $\alpha^2$ (B) Cru, which combined make up the 13th visually brightest star in the night sky. Here we make use of archival VLTI data of $\alpha$ Cru A+B in order to study its multiplicity and orbital architecture. The data spatially resolved the close (6 mas) companion in $\alpha$ Cru A (a known spectroscopic binary) and revealed that $\alpha