|Observation data: J2000.0 epoch|
|Right ascension||08h 00m :s|
|Declination||−43° 00′ :″|
|Distance||1470 ly (450 pc)|
|Apparent magnitude (V)||+12 (infrared only)|
|Absolute magnitude (V)||3.73 (infrared)|
The Gum Nebula (Gum 12) is an emission nebula that extends across 36° in the southern constellations Vela and Puppis. It lies roughly 350 parsecs from the Earth. Hard to distinguish, it was widely believed to be the greatly expanded (and still expanding) remains of a supernova that took place about a million years ago. More recent research suggests it may be an evolved H II region. It contains the 11,000-year-old Vela Supernova Remnant, along with the Vela Pulsar.
The Gum Nebula contains about 32 cometary globules. These dense cloud cores are subject to such strong radiation from O-type stars γ2 Vel and ζ Pup and formerly the progenitor of the Vela Supernova Remnant that the cloud cores evaporate away from the hot stars into comet-like shapes. Like ordinary Bok globules, cometary globules are believed to be associated with star formation.
It is named after its discoverer, the Australian astronomer Colin Stanley Gum (1924–1960). Gum had published his findings in 1955 in a work called A study of diffuse southern H-alpha nebulae (see Gum catalog).
- Gum Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- APOD: Gum Nebula, with mouse over (2009.08.22)
- Galaxy Map: Entry for Gum 12 in the Gum Catalog
- Galaxy Map: Detail chart for the Gould Belt (showing the location of Gum 12 relative to the sun)
- Encyclopedia of Science: Entry for the Gum Nebula (erroneously called Gum 56)