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> The Jewel Box star cluster

The Jewel Box star cluster

author: Nasa/ESA/Novapix

reference: a-aou47-55005

Image Size 300 DPI: 25 * 12 cm

This image is a "close-up' view from the NASA/ESA Hubble Space Telescope of NGC 4755, or the Jewel Box cluster. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly coloured stars are visible in the image, as well as many much fainter ones, often with intriguing colours. The huge variety in brightness exists because the brighter stars are 15 to 20 times the mass of the Sun, while the dimmest stars are less than half the mass of the Sun. This is the first image of an open galactic cluster with imaging extending from the far ultraviolet to the near-infrared. NGC 4755 (Caldwell 94) is called the Jewel Box, based on John Herschel's comment in the 1830's that it looked like a superb piece of jewelry. There are about 50 stars in this cluster which formed some 16 million years ago. Most of the cluster members are blue giants which in a few million years will exhaust their hydrogen fuel and become red giants on their way to a cataclysmic end as supernovae. One red giant can already be seen at the center of the cluster (top right).

Keywords for this photo:

2009 - ASTRONOMY - BLUE GIANT - CRUX - HST - HUBBLE SPACE TELESCOPE - JEWEL BOX - NGC 4755 - OPEN CLUSTER - RED GIANT - RED SUPERGIANT - SOUTHERN HEMISPHERE - STAR - STAR CLUSTER - SUPERGIANT - TWINKLING -