Messier 14

Lore & Background

Messier 14 was discovered by Charles Messier in 1764. At a distance of about 30,000 light-years, it contains several hundred thousand stars. Its shape is decidedly elongated, and it is about 100 light-years across. The total luminosity of M14 is in the order of 400,000 times that of the Sun, corresponding to an absolute magnitude of −9.12. A total of 70 variable stars are known in M14, many of the W Virginis variety common in globular clusters. In 1938, a nova appeared, although this was not discovered until photographic plates from that time were studied in 1964. It is estimated that the nova reached a maximum brightness of magnitude +9.2, over five times brighter than the brightest 'normal' star in the cluster. Slightly over 3° southwest of M14 lies the faint globular cluster NGC 6366.

Reader's Guide

Messier 14 is significant as a globular cluster discovered by Charles Messier in 1764, adding to the catalog of deep-sky objects. Its elongated shape distinguishes it from many other globular clusters. The cluster's large number of variable stars, particularly of the W Virginis type, makes it a subject of study for stellar evolution. The most notable event in its history is a nova that occurred in 1938 but was not identified until 1964 from archival photographic plates. This nova reached a magnitude of +9.2, far outshining the cluster's brightest normal star. The cluster is easily observed with binoculars due to its apparent magnitude of +7.6, while medium-sized telescopes can resolve some of its individual stars, the brightest of which is magnitude +14. Its legacy includes being a target for amateur astronomers and a subject in astronomical databases and images, such as the NASA Astronomy Picture of the Day featuring the cluster alongside a comet.

Did You Know?

• A nova in M14 occurred in 1938 but was not discovered until 1964.
• The cluster contains 70 known variable stars, many of the W Virginis type.
• The brightest normal star in M14 has a magnitude of +14.