Gum Nebula

Gum nebula
Observational Data
Designation	Gum 12a
Right ascension	07h 53m[1]
Declination	-42° 06′[1]
Constellation	Puppis
Type of object	Emission nebula
Dimensions	35° across[2]
Magnitude	Apparent Mag: >6
Astrometry
Distance from Earth	1,300 ly[3]

The Gum nebula (Gum 12a) is a large emission nebula in the constellations of Puppis and Vela.^[2] A complex cloud of gas, it is the largest emission nebula on the night sky, measured by its apparent size of 35°.^[2] This large size actually makes it difficult to see or photograph. Photographs of the nebula are normally made from a mosaic of zoomed in photographs. The nebula was discovered by the Australian astrophysicist Colin S. Gum whilst working at the Mount Stromlo Observatory in Australia^[4] Gum gave the nebula the designation Gum 12a in his catalogue, the Gum Catalgoue, which is still in use today. It has been proposed that is the remnant of a supernova.^[2] The Vela supernova remnant is contained within this nebula.^[5]

Properties and Structure[edit]

At 35° across, the Gum nebula is by far the largest emission nebula known and covers an area of sky several times that of the Moon. It's distance of some 1,300 light years means that is roughly 1,000 light years across.^[2] The radiation emitted by two stars located within the nebula, ζ Puppis and γ² Velorum, caused the hydrogen gas in the nebula to glow.^[3] The gas in the nebula has a density of around 2 particles cm⁻³.^[3]

References[edit]