Doubly ionized oxygen: Difference between revisions

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{{Short description|Oxygen ion in astronomy and atomic physics}}

[[File:Oiii-linesp.svg|thumb|right|EmissionA lines[[Grotrian diagram]] of doubly ionized oxygen: The forbidden linestransitions in the visible spectrum are shown in green.]]

'''Doubly ionized oxygen''' (also known as '''<nowiki>[O III]</nowiki>''') is a [[forbidden line]] of the [[ion]] [[oxygen|O]]²⁺. It is significant in that it emits light in the green part of the spectrum primarily at the wavelength 500.7 nanometres (nm) and secondarily at 495.9&nbsp;nm. Concentrated levels of <nowiki>[O III]</nowiki> are found in [[diffuse nebula|diffuse]] and [[planetary nebula|planetary]] nebulae. Consequently, narrow [[Dichroic filter|band-pass filter]]s that isolate the 501&nbsp;nm and 496&nbsp;nm wavelengths of light are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light polluted terrestrial atmosphere) where the frequencies of <nowiki>[O III]</nowiki> are much less pronounced.

In [[astronomy]] and [[atomic physics]], '''doubly ionized oxygen''' is the [[ion]] [[oxygen|O]]²⁺ ('''O III''' in [[spectroscopic notation]]).

==Ion==

These [[emission line]]s were first discovered in the spectrums of planetary nebulae in the 1860s. At that time, they were thought to be due to a new element which was named ''[[nebulium]]''. In 1927, [[Ira Sprague Bowen]] came up with the current explanation of them being due to doubly ionized oxygen.<ref>{{cite journal | doi = 10.1038/120473a0 | title = The Origin of the Nebulium Spectrum | year = 1927 | author = Bowen, I. S. | journal = Nature | volume = 120 | issue = 3022 | pages = 473|bibcode = 1927Natur.120..473B }}</ref>

'''DoublyIts ionizedemission oxygen''' (also known as '''<nowiki>[O III]</nowiki>''') is aof [[forbidden line]]s ofin the [[ion]]visible [[oxygen|Ospectrum]]²⁺. It is significant in that it emits light in the green part of the spectrumfall primarily at the wavelength 500.7 nanometres (&nbsp;nm), and secondarily at 495.9&nbsp;nm. Before spectra of oxygen ions became known, these lines once led to a spurious identification of the substance as a new [[chemical element]]. Concentrated levels of <nowiki>[O III]</nowiki> are found in [[diffuse nebula|diffuse]] and [[planetary nebula|planetary]] nebulae]]. Consequently, narrow [[Dichroic filter|band-pass filter]]s that isolate the 501500.7&nbsp;nm and 496495.9&nbsp;nm wavelengths of light, that correspond to [[green]]-[[turquoise (color)|turquoise]]-[[cyan]] [[spectral colors]], are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly [[light pollution|light-polluted]] terrestrial atmosphere) where the frequencies of <nowiki>[O III]</nowiki> are much less pronounced.

These [[emission line]]s were first discovered in the spectrumsspectra of [[planetary nebula|planetary nebulae]] in the 1860s. At that time, they were thought to be due to a new element which was named ''[[nebulium]]''. In 1927, [[Ira Sprague Bowen]] came up withpublished the current explanation ofidentifying themtheir beingsource due toas doubly ionized oxygen.<ref>{{cite journal | doi = 10.1038/120473a0 | title = The Origin of the Nebulium Spectrum | year = 1927 | author = Bowen, I. S. | journal = Nature | volume = 120 | issue = 3022 | pages = 473|bibcode = 1927Natur.120..473B | doi-access = free }}</ref>

Other transitions include the forbidden 88.4&nbsp;μm and 51.8&nbsp;μm transitions in the far [[infrared]] region.<ref name="Osterbrock">{{cite book |last1=Osterbrock |first1=Donald E. |title=Astrophysics of gaseous nebulae and active galactic nuclei |date=1989 |publisher=University Science Books |___location=Mill Valley, Calif. |isbn=0935702229 |page=73}}</ref>

Permitted lines of O III lie in the middle [[ultraviolet]] band and are hence inaccessible to terrestrial astronomy.

In the Gas Pillars of the ''[[Eagle Nebula]]''. Doubly-ionized oxygen atoms emit blue light.

== See also ==

* [[H II region]]

* [[Emission nebula]]

== References ==

<references/>

{{Allotropes of oxygen}}

[[Category:AtomicIons|O physicsIII]]

[[Category:Astronomical spectroscopy|O III]]

[[Category:Oxygen]]

{{science-stub}}

[[fr:Oxygène doublement ionisé]]

[[pt:Oxigénio duplamente ionizado]]

[[ru:Дважды ионизированный кислород]]

[[zh:雙電離氧]]