Alpha Crucis

Template: Infobox double star / Maintenance / single coordinate

Acrux is the brightest star in the constellation of the Southern Cross ( Crux ) and the zwölfthellste of heaven. Since it is very far to the south, he was not given a proper name in the European cultures; the name Acrux is simply formed from alpha and Crux. In astronomy he is systematically referred to as α Crucis or short α Cru, according to follow Becrux and Gacrux.

With an apparent magnitude of 0.77 like it is the southernmost first-magnitude star.

In fact, it involves a multiple star system located about 320 light -years from the solar system. The two optically separable components, α and α ² ¹ Crucis Crucis, have an angular separation of 4.29 "on. ¹ α Cru has an apparent magnitude of 1.3 may, α ² Cru of 1.6 mag. Both are hot stars of spectral type B, with surface temperatures of 28,000 K and 26,000 K and a luminosity of about 25000 -. . 16000 or times the sun A circumambulation take so long that the orbital motion is difficult to discern from their minimum distance of 430 AE it is found to be at least 1500 years, but is probably much longer. α ¹ Cru is itself a spectroscopic binary, whose components are the 14 - and 10 -fold adopts solar mass. They circle each other in only 76 days at a distance of about 1 AU. Another sub- giant located in about 90 "Distance from Acrux at a position angle of 202 degrees and has the same spatial direction of motion, so he could be gravitationally bound to the Acrux system. However, if he is close indeed lie at Acrux, he would be for his class quite faint. Presumably, with him rather an optical double star, which is more than twice as far as Acrux away.

The masses of the lighter components of α and α ² ¹ Cru Cru suggest that they will explode at the end of its life as a supernova. The weaker component of α ¹ Cru could end up as a white dwarf it.