The Gum Nebula (Gum 12) is an

emission nebula An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star. Among the several different types of emissio ...

that extends across 36° in the southern constellations

Vela Vela or Velas may refer to: Astronomy * Vela (constellation), a constellation in the southern sky (the Sails) ** Vela (Chinese astronomy) ** Vela Pulsar ** Vela X-1, a pulsing, eclipsing high-mass X-ray binary system Places * Vela Bluff, Antarc ...

and

Puppis Puppis is a constellation in the southern sky. Puppis, the Latin translation of " poop deck", was originally part of an over-large constellation Argo Navis (the ship of Jason and the Argonauts), which centuries after its initial description, w ...

. It lies approximately 450

parsecs The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, a ...

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 An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundre ...

. It contains the 11,000-year-old

Vela Supernova Remnant __NOTOC__ The Vela supernova remnant is a supernova remnant in the southern constellation Vela. Its source Type II supernova exploded approximately 11,000–12,300 years ago (and was about 800 light-years away). The association of the Vela super ...

, along with the

Vela Pulsar The Vela Pulsar (PSR J0835-4510 or PSR B0833-45) is a radio, optical, X-ray- and gamma-emitting pulsar associated with the Vela Supernova Remnant in the constellation of Vela. Its parent Type II supernova exploded approximately 11,00 ...

. The Gum Nebula contains about 32 cometary globules. These dense cloud cores are subject to such strong radiation from

O-type star An O-type star is a hot, blue-white star of spectral type O in the Yerkes classification system employed by astronomers. They have temperatures in excess of 30,000 kelvin (K). Stars of this type have strong absorption lines of ionised helium, s ...

s γ² Vel and ζ Pup and formerly the progenitor of the

that the cloud cores evaporate away from the hot stars into comet-like shapes. Like ordinary

Bok globule In astronomy, Bok globules are isolated and relatively small dark nebulae, containing dense cosmic dust and gas from which star formation may take place. Bok globules are found within H II regions, and typically have a mass of about 2 to 50 so ...

s, cometary globules are believed to be associated with star formation. It is named after its discoverer, the Australian astronomer

Colin Stanley Gum Colin Stanley Gum (4 June 1924 – 29 April 1960) was an Australian astronomer known for his cataloguing of emission nebulae and the publication of his findings. Early life and education Gum was born at Quambi Hospital in Adelaide, South Austr ...

(1924–1960). Gum had published his findings in 1955 in a work called ''A study of diffuse southern H-alpha nebulae'' (see

Gum catalog The Gum catalog is an astronomical catalog of 84 emission nebulae in the southern sky. It was made by the Australian astronomer Colin Stanley Gum (1924-1960) at Mount Stromlo Observatory using wide field photography. Gum published his findings ...

). The Gum nebula was photographed during Apollo 16 while the command module was in the double umbra of the Sun and Earth, using high-speed Kodak film. AS16-127-20024

Popular culture

The Gum Nebula is explored by the crew of the ''Starship Titan'' in the ''

Star Trek ''Star Trek'' is an American science fiction media franchise created by Gene Roddenberry, which began with the eponymous 1960s television series and quickly became a worldwide pop-culture phenomenon. The franchise has expanded into vario ...

'' novel '' Orion's Hounds''.

References

External links

*
APOD
Gum Nebula, with mouse over (2009.08.22)
Galaxy Map
Entry for Gum 12 in th
Gum Catalog

Detail chart for the

Gould Belt The Gould Belt is a local, partial ring of stars in the Milky Way, about 3,000 light-years long, tilted away from the galactic plane by about 16–20 degrees. It contains many O- and B-type stars, amounting to the nearest star-forming regio ...

(showing the location of Gum 12 relative to the sun)
Encyclopedia of Science
Entry for the Gum Nebula (erroneously called Gum 56)

{{Gum catalogue Emission nebulae Puppis Vela (constellation)

Popular culture

See also

References

External links