A red supergiant and among the brightest in the sky. A member of the Sco OB1 association (formerly) it is now evolved from an O9V star at birth. After 17.5 Million years it's now a M0Iab. 15 times mass solar, and 835 times the radius, it serves as a stable anchor point to determine the masses and ages of the Association. Altogether a part of the Sco-Cen Group, It is the most evolved known member. It is a binary with a B2V (more appropiately B6V) at 535 AU from the star, which is also the rainbow to the left edge of the star due to spectral and visual mixing.