AAO image reference AAT 111. « Previous || Next »
Top left is NE. Image width is about 12 arc min
Image and text © 1987-2002, Anglo-Australian Observatory, photograph by David Malin.
Click here for bigger image.
Globular clusters are among the oldest objects known. The stars within them seem to contain much less of the 'metals' that are found in other stars, and since the universe was almost completely metal-free (i.e. contained only hydrogen and helium) in the beginning, it seems that globular cluster stars were among the first stellar objects to form. However, it is certain these beautiful, compact cities of stars did not look like this in their youth, when they would have been much brighter, their light dominated by hot massive stars that have vanished.
This particular globular cluster is in the deep southern sky in Pavo and is at a distance of about 14,000 light years. It is a little brighter than the much better known cluster M13 and is just visible to the unaided eye. The colours of the stars are subtle but this picture clearly shows the cool but bright red giant stars whose light dominates the cluster. The cluster is in a particularly obscuration-free part of the sky, so, despite its distance we see the colors almost unaffected by interstellar dust.
Entry from NGC 2000.0 (R.W. Sinnott, Ed.) © Sky Publishing Corporation, 1988:
NGC 6752 Gb 19 10.9 -59 59 s Pav 20.45.4 glob. cl. , B, vL, iR, rrr, st 11...16