M70

M70

Messier 70 or M70, also known as NGC 6681, is a globular cluster of stars in the southern constellation of Sagittarius. It was discovered by Charles Messier on August 31, 1780. The famous comet Hale–Bopp was discovered near this cluster July 23, 1995.

M70 is at a distance of about 29,400 light years away from Earth and around 6,500 light-years from the Galactic Centre. It is roughly the same size and luminosity as its neighbour in space, M69. M70 has a very small core radius of 0.22 ly (0.068 pc) and a half-light radius of 182.0 ly (55.80 pc). This cluster has undergone core collapse, leaving it centrally concentrated with the luminosity distribution following a power law.

There are two distinct stellar populations in the cluster, with each displaying unique abundance abundances. These likely represent different generations of stars. Five known variable stars lie within the tidal radius of this cluster, all of which are RR Lyrae variables. The cluster may have two blue stragglers near the core.