M53

Messier 53 (M53) is a globular star cluster located in the northern constellation Coma Berenices. The cluster has an apparent magnitude of 8.33 and lies at an approximate distance of 58,000 light years from Earth. It has the designation NGC 5024 in the New General Catalogue.

Messier 53 is relatively easy to find as it lies in the same area of the sky as Arcturus, the fourth brightest star in the sky. Arcturus can be easily found by following the line formed by the three bright stars of the Big Dipper‘s handle. Arcturus is the first bright star that appears along the imaginary line.Messier 53 can be found 15 degrees west of the orange giant. Located in the eastern part of Coma Berenices, M53 is positioned just a degree to the northeast of Diadem, Alpha Comae Berenices, an optical double star with a visual magnitude of 4.32.Diadem can be found by following a line drawn from Arcturus via Muphrid, Eta Boötis, for about 11 degrees to the west.Small telescopes reveal a hazy patch, slightly oval in shape, with a large bright core, while larger instruments resolve the cluster’s outer regions into stars. At least a medium-sized telescope is required to resolve the stars and significantly larger ones to see the full diameter of the cluster’s outer halo. The best time of year to observe M53 is in the months of March, April and May.

@Messier-Objects.com

NGC5053

NGC 5053 is the New General Catalogue designation for a globular cluster in the northern constellation of Coma Berenices. It was discovered by German-British astronomer William Herschel on March 14, 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.There are ten known RR Lyrae variable stars in this cluster with masses ranging from 68% to 78% of the solar mass. Nine of these variables were reported by German astronomer Walter Baade in 1928, and the tenth by American astronomer Helen Sawyer in 1946.  The cluster hosts 27 known blue stragglers, of which five are short period SX Phoenicis variable stars.NGC 5053 is a relatively low mass cluster with a low core concentration factor of 1.32. 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. 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.

DIADEM (42 COM)Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary starin the constellation of Coma Berenices (Berenice's Hair), 17.8 parsecs (58 ly) away. It consists of two main sequence stars, each a little hotter and more luminous than the Sun.Alpha Comae Berenices is said to represent the crown worn by Queen Berenice. The two components are designated Alpha Comae Berenices A (officially named Diadem/ˈdaɪədɛm/, the traditional name for the system) and B.