NGC 4755: A Jewel Box of Stars

The great variety of star colors in this open cluster underlies its name: The Jewel Box . One of the bright central stars is a red supergiant, in contrast to the many blue stars that surround it. The cluster , also known as Kappa Crucis contains just over 100 stars, and is about 10 million years old. Open clusters are younger, contain few stars, and contain a much higher fraction of blue stars than do globular clusters . This Jewel Box lies about 7500 light-years away, so the light that we see today was emitted from the cluster before even the Great Pyramids in Egypt were built. The Jewel Box, pictured above , spans about 20 light-years, and can be seen with binoculars towards the southern constellation of Crux .