Globular cluster M79 in Lepus
author: Nasa/ESA/Novapix
reference: a-agb19-04003
Image Size 300 DPI: 11 * 11 cm
The globular cluster M79 (NGC 1904) is located about 41 000 light year away in Lepus. M79 contains about 150,000 stars packed into an area measuring only 118 light-years across. These giant "star-globes" contain some of the oldest stars in our galaxy, estimated to be 11.7 billion years old.
In the Hubble image, Sun-like stars appear yellow. The reddish stars are bright giants that represent the final stages of a star's life. Most of the blue stars sprinkled throughout the cluster are aging "helium-burning" stars. These bright blue stars have exhausted their hydrogen fuel and are now fusing helium in their cores.
A scattering of fainter blue stars are "blue stragglers." These unusual stars glow in blue light, mimicking the appearance of hot, young stars. Blue stragglers form either by the merger of stars in a binary system or by the collision of two unrelated stars in M79's crowded core.