Hubble image of
globular cluster Messier 79 which is 41,000 light years away in the constellation Lepus (the Hare). It contains about 150,000 stars whose mutual gravity pulls them together into a somewhat spherical shape. Clusters like this contain some of the oldest stars in the Galaxy, some nearly 12 billion years old.
Most of the bright blue stars have used up their hydrogen fuel and are fusing helium which releases more energy and makes them hotter. The reddish stars are giants in their final states of life. The yellow stars are similar to the Sun.
Pierre Méchain discovered the cluster in 1780 and reported it to
Charles Messier, who included it in his catalog. Several years later, William Herschel with his large telescope resolved the stars in M79, and described it as a “globular star cluster.â€
Credit: NASA and ESA
Acknowledgment: S. Djorgovski (Caltech) and F. Ferraro (University of Bologna)