M53
M 53 (also known as NGC 5024) is a globular cluster, discovered by Johann Elert Bode in 1775.
M53 is one of the more outlying globular clusters, being about 60,000 light-years (18.4 kpc) light-years away from the Galactic Center, and almost the same distance (about 58,000 light-years (17.9 kpc)) from the Solar System.

This is considered a metal-poor cluster and at one time was thought to be the most metal-poor cluster in the Milky Way. Abundance measurements of cluster members on the red giant branch show that most are first-generation stars. That is, they did not form from gas recycled from previous generations of stars. This differs from the majority of globular clusters that are more dominated by second generation stars. The second generation stars in M53 tend to be more concentrated in the core region. Overall, the stellar composition of cluster members is similar to members of the Milky Way halo.

The cluster displays various tidal-like features including clumps and ripples around the cluster, and tails along the cluster's orbit in an east–west direction. A tidal bridge-like structure (not visible in the image here) appears to connect M53 with the close, very diffuse neighbor NGC 5053, as well as an envelope surrounding both clusters. These may indicate a dynamic tidal interaction has occurred between the two clusters; a possibly unique occurrence within the Milky Way since there are no known binary clusters within the galaxy. In addition, M53 is a candidate member of the Sagittarius dwarf galaxy tidal stream.

Mass    8.26×105 M☉
Metallicity    [ Fe / H ] = –1.86 dex
Estimated age    12.67 Gyr

NGC5053
NGC 5053 was discovered by German-British astronomer William Herschel in 1784 and cataloged as VI-7. In his abbreviated notation, he described it as, "an extremely faint cluster of extremely small stars with resolvable nebula 8 or 10′ diameter, verified by a power of 240, beyond doubt". Danish-Irish astronomer John Louis Emil Dreyer reported in 1888 that the cluster appeared, "very faint, pretty large, irregular round shape, growing very gradually brighter at the middle".

This is a metal-poor cluster, meaning the stars have a low abundance of elements other than hydrogen and helium—what astronomers term metallicity. As recently as 1995, it was considered the most metal-poor globular cluster in the Milky Way. The chemical abundances of the stars in NGC 5053 are more similar to those in the dwarf galaxy Sagittarius Dwarf Spheroidal Galaxy than to the Milky Way halo. Along with the kinematics of the globular cluster, this suggests that NGC 5053 may have been stripped from the dwarf galaxy.

NGC 5053 is a relatively low mass cluster with a low core concentration. It sports a stream of tidal debris to the west with a projected length of 1.7 kpc. This stream may have been created through shock-induced processes. The cluster is located less than 1° from Messier 53 and the two have nearly the same distance modulus, which corresponds to a spatial separation of around 2 kpc. As already mentioned above, there is a tidal bridge joining M53 to NGC 5053, suggesting the pair may have interacted in the past. The cluster is following an orbit through the Milky Way that has a perigalacticon distance of 9 kpc and an orbital eccentricity of 0.84. At present, it is 18.4 kpc from the Galactic Center, with a radial velocity of 42.0±1.4 km/s.

Metallicity    [ Fe / H ] = −2.30 dex
Estimated age    12.3±0.7 Gyr