a Crucis

α Crucis

[¦al·fə ′krü·səs]
(astronomy)
A double star in the constellation Crux that is 220 light-years from the sun; spectral classification BO.5V. Also known as Acrux.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.