Messier 62, NGC 6266

Messier 62 is a globular cluster in the constellation Ophiuchus, and one of the most irregularly shaped globulars known. It was discovered in 1771 by Charles Messier, and first resolved into stars by William Herschel, who also noted its shape.

With an apparent size of 15' and a visual magnitude of 6.5, Messier 62 appears very similar to its neighbor, M 19. But M 62 is one of the most irregular of all globular clusters, making it look like a comet in a small telescope; its central condensation is significantly displaced from the geometric center.

M 62 is 25,500 light-years away, and measures some 100 light-years across. The globular's irregular shape may result from its close distance to the galactic center - only about 6100 light-years - resulting in deformation by tidal forces. The core of M 62 is extremely dense, and has possibly undergone a core collapse sometime in its history, similar to a number of other globulars including M 15, M 30, and M 70.

From studies conducted in the 1970s, M 62 is known to contain nearly 90 variable stars, many of them of the RR Lyrae type. The globular also contains a number of X-Ray sources, thought to be close binary star systems and millisecond pulsars in binary systems. These stellar systems are thought to have formed in close encounters of the globular cluster's member stars; apparently, such encounters have occurred frequently in M 62.