Kappa Crucis (star)

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Kappa Crucis (κ Cru) is a bright star in the open cluster NGC 4755, the Jewel Box Cluster. It is one of the cluster’s brightest members and helps form the “A” shape at the cluster’s center. κ Cru is a B3 Ia bright supergiant and is a spectroscopic binary, meaning it has a hidden companion detected by changes in its spectrum. It shines more than 100,000 times brighter than the Sun, thanks to its high temperature of about 16,300 K and its large size. Its apparent magnitude is 5.98, so it’s just visible to the naked eye in dark skies. The Jewel Box Cluster lies several thousand light-years away (roughly 7,500–8,500 ly) in the Centaurus region, and the cluster is about 11 million years old.