APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
NGC 4755: A Jewel Box of Stars
Explanation: 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 6,400 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 the cross ( Crux ).
| Date | August 17, 2010 |
|---|---|
| Credit | Credit & Copyright: Dieter Willasch ( Astro-Cabinet ) |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



