The third brightest of the stars that make up Crux the Cross, the red colouration of Gacrux contrasts against the three bluestars that make up the Cross' other three arms. There is indirect evidence that Gacrux has a white dwarf companion, though this companion has yet to be directly observed.
The Galactic position and direction of Gacrux relative to Earth'sSun. Note that, at this
extreme scale, the two stars are effectively in the same place.
The crowning star of the Southern Cross is
Gacrux or Gamma Crucis, 89 light years (27 parsecs) from
Earth. This is a redgiantstar, indicating that it is reaching the end of its stellar lifespan. It is a
binary (that is, it has an less luminous and smaller companion
star), and is also variable - its
brightness changes over time.