Becrux

Becrux (also known as Mimosa) is the second brightest star in the constellation Crux (the Southern Cross) at magnitude 1.25. It is a blue giant of spectral type B0.5III, located about 280 light-years from Earth. Becrux is about 16 times the mass of the Sun and roughly 34,000 times more luminous. It is a Beta Cephei-type variable star, pulsating with multiple periods between 4 and 6 hours, causing small brightness fluctuations of a few hundredths of a magnitude.

Becrux marks the eastern (left) arm of the Southern Cross and is visible only from latitudes south of about 20°N. The Cross is best located by using the Southern Pointers (Alpha and Beta Centauri), which point toward it. Becrux's blue-white color contrasts beautifully with the reddish Gacrux (Gamma Crucis) at the top of the Cross. The famous Jewel Box Cluster (NGC 4755) lies just 1 degree southeast of Becrux. Best observed from March through July from southern latitudes.

The name Mimosa may derive from the flower, though its origin is uncertain. The alternative name Becrux is a modern contraction of 'Beta Crucis.' The Southern Cross has been used for navigation by sailors in the Southern Hemisphere for centuries, and it appears on the national flags of Australia, New Zealand, Brazil, Papua New Guinea, and Samoa.