Astronomers at ESO’s La Silla Observatory, Chile, have released a new image of the globular star cluster Messier 4.
This image shows the spectacular globular star cluster Messier 4 (ESO / ESO Imaging Survey)
Messier 4, also known as NGC 6121, is a globular cluster full of ancient stars in the constellation of Scorpius approximately 7,200 light years away. It is one of the closest and most studied of the globular clusters and recent work has revealed that one of its stars has strange and unexpected properties, apparently possessing the secret of eternal youth. This bright object can be easily seen in binoculars, close to the bright red star Antares.
The new image from the Wide Field Imager (WFI) on ESO’s MPG/ESO 2.2-m telescope reveals many more of the cluster’s tens of thousands of stars and shows the cluster against the rich background of the Milky Way.
The astronomers have also studied many of the stars in the cluster individually using instruments on ESO’s Very Large Telescope. By splitting the light from the stars up into its component colors they can work out their chemical composition and ages.
New results for the stars in Messier 4 have been surprising. The stars in globular clusters are old and hence not expected to be rich in the heavier chemical elements. This is what is found, but one of the stars in a recent survey was also found to have much more of the rare light element lithium than expected. The source of this lithium is mysterious. Normally this element is gradually destroyed over the billions of years of a star’s life, but this one star amongst thousands seems to have the secret of eternal youth. It has either somehow managed to retain its original lithium, or it has found a way to enrich itself with freshly made lithium.
