Acrux Alpha Crucis

Stellar classification



  • X 277
  • Y -3
  • Z 163
→ Sol: 321

Object type

  • Spectroscopic binary
  • Star
  • Double or multiple star
  • UV-emission source
simbad:* alf01 Cru


Alpha Crucis (α Crucis, abbreviated Alpha Cru, α Cru) is a multiple star system located 321 light-years from the Sun in the constellation of Crux and part of the asterism known as the Southern Cross. With a combined visual magnitude of 0.76, it is the brightest star in Crux and the 13th brightest star in the night sky. It is the southernmost first-magnitude star, just a little more southerly than Alpha Centauri.

Alpha Crucis appears as a single star to the naked eye, but it is actually a multiple star system with several stars. Two components are visually distinguishable: α1 Crucis and α2 Crucis; alternatively designated α Crucis A and α Crucis B. Both are B-type stars, and are many times more massive and luminous than the Sun. α1 Crucis is itself a spectroscopic binary with components designated α Crucis Aa (also named Acrux) and α Crucis Ab. Its two component stars orbit every 76 days at a separation of about 1 astronomical unit (au).

This article uses material from the Wikipedia article "Alpha Crucis", which is released under the Creative Commons Attribution-Share-Alike License 3.0.