Gum catalog

Lore & Background

The Gum catalog was published in a 1955 study entitled 'A study of diffuse southern H-alpha nebulae', which presented 84 nebulae or nebular complexes. Gum, an Australian astronomer working at Mount Stromlo Observatory, used wide-field photography to identify these objects in the southern sky. Many Gum objects are also listed in similar catalogs such as the Sharpless catalog and the RCW catalog, though the RCW and Gum catalogs were mainly of the southern hemisphere due to Mount Stromlo's location. The most famous entry is Gum 12, known as the Gum Nebula, an emission nebula located in the southern constellations Vela and Puppis.

Reader's Guide

The Gum catalog holds significance as one of the major surveys of emission nebulae in the southern sky, complementing northern-hemisphere catalogs. Its entries overlap substantially with the RCW catalog, reflecting the collaborative nature of southern nebular astronomy. The catalog's most prominent object, Gum 12 (the Gum Nebula), is a large emission nebula spanning parts of Vela and Puppis, and it bears the discoverer's name.

The catalog remains a reference for studies of H-alpha nebulae and star-forming regions in the southern hemisphere, though it is less widely cited than the Sharpless or RCW catalogs. Its legacy is tied to the work of Colin Gum, whose early death at age 36 cut short a promising career. The catalog continues to be used by astronomers and astrophotographers interested in southern diffuse nebulae.