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not to micromanage, but a couple tweaks
==Properties and Structure==
==Properties and Structure==
The nebula is thought to lie approximately 5,000 [[light year]]s from Earth.<ref name=nasa/> However some sources put it lower at only 4,200 light years.<ref name=constellation-guide/> Therefore its apparent size of 1 arcminute corresponds to a physical size of 1.22-1.55 ly across.<ref>By direct calculation using distances of 4,200 and 5,000 ly.</ref> It is thought to have a radius of 0.7 ly. There is a [[star]] at the centre of the nebula, though it is obscured by gas. It is thought to be surrounded by rotating gas in the shape of a [[torus]] (doghnut).<ref>Demurs, J., Sánchez Contreras, C., Bujarrabal, V., Colomer, F. and Alcolea, J. (2001). Detection of an inner torus in the protoplanetary nebulae OH231.8+4.2. In: ''Cosmic Masers: From Proto-Stars to Black Holes''. San Francisco: Astronomical Society of the Pacific, p.334. [https://arxiv.org/abs/astro-ph/0109543 arXiv:astro-ph/0109543] [http://adsabs.harvard.edu/abs/2002IAUS..206..344D Bibcode:2002IAUS..206..344D]</ref>
The nebula is thought to lie approximately 5,000 [[light year]]s from Earth.<ref name=nasa/> However some sources put it lower at only 4,200 light years.<ref name=constellation-guide/> Therefore its apparent size of 1 arcminute corresponds to a physical size of 1.22-1.55 ly across.<ref>By direct calculation using distances of 4,200 and 5,000 ly.</ref> It is thought to have a radius of 0.7 ly. There is a [[star]] at the centre of the nebula, though it is obscured by gas. It is thought to be surrounded by rotating gas in the shape of a [[torus]] (doughnut).<ref>Demurs, J., Sánchez Contreras, C., Bujarrabal, V., Colomer, F. and Alcolea, J. (2001). Detection of an inner torus in the protoplanetary nebulae OH231.8+4.2. In: ''Cosmic Masers: From Proto-Stars to Black Holes''. San Francisco: Astronomical Society of the Pacific, p.334. [https://arxiv.org/abs/astro-ph/0109543 arXiv:astro-ph/0109543] [http://adsabs.harvard.edu/abs/2002IAUS..206..344D Bibcode:2002IAUS..206..344D]</ref>
Vast quantities of material are being ejected by the [[star]] at high speed in opposite directions. This has created the bipolar (two lobed) structure that is apparent in images of the nebula. The fastest gas is shown in yellow and is moving at over one million kilometers per hour (621,371 miles per hour).<ref name=nasa/> When this gas slams into the surrounding interstellar gas, a [[supersonic]] shock front forms.<ref name=apod>[https://apod.nasa.gov/apod/ap170215.html The Calabash Nebula from Hubble] from apod.nasa.gov</ref> [[Sulphur]] containing [[molecule]]s such as sulphur dioxide and hydrogen sulphide has been discovered through [[radio astronomy|radio observations]] of the nebula.<ref name=constellation-guide/> These molecules are thought to have been formed by the supersonic shock.
Vast quantities of material are being ejected by the [[star]] at high speed in opposite directions. This has created the bipolar (two lobed) structure that is apparent in images of the nebula. The fastest gas is shown in yellow and is moving at over one million kilometers per hour (621,371 miles per hour).<ref name=nasa/> When this gas slams into the surrounding interstellar gas, a [[supersonic]] shock front forms.<ref name=apod>[https://apod.nasa.gov/apod/ap170215.html The Calabash Nebula from Hubble] from apod.nasa.gov</ref> [[Sulphur]] containing [[molecule]]s such as sulphur dioxide and hydrogen sulphide has been discovered through [[radio astronomy|radio observations]] of the nebula.<ref name=constellation-guide/> These molecules are thought to have been formed by the supersonic shock.
The color of the gas in the nebula depends on its composition. Blue corresponds to [[ionization|ionized]] [[nitrogen]] and [[hydrogen]].<ref name=apod/>
The color of the gas in the nebula depends on its composition. Blue corresponds to [[ionization|ionized]] [[nitrogen]] and [[hydrogen]].<ref name=apod/>
==References==
{{reflist}}
==External links==
==External links==
*[https://youtu.be/zEQbfNY-hyk 3D visulazation of the Calabash nebula] on [[Youtube]]
*[https://youtu.be/zEQbfNY-hyk 3D visulazation of the Calabash nebula] on [[Youtube]]
{{Nebulae}}
{{Nebulae}}