Editing Hydroxy group (section)

==Planetary observations==

===Airglow of the Earth===

The Earth's night sky is illuminated by diffuse light, called [[airglow]], that is produced by radiative transitions of atoms and molecules.<ref>{{cite journal | vauthors = Silverman SM | title = Night airglow phenomenology. | journal = Space Science Reviews | date = October 1970 | volume = 11 | issue = 2 | pages = 341–79 | doi = 10.1007/BF00241526
| bibcode = 1970SSRv...11..341S |bibcode-access=free | s2cid = 120677542 |url=http://adsabs.harvard.edu/full/1970SSRv...11..341S |url-status=live |archive-url=https://web.archive.org/web/20231005001746/https://adsabs.harvard.edu/full/1970SSRv...11..341S |archive-date= Oct 5, 2023 }}
</ref> Among the most intense such features observed in the Earth's night sky is a group of infrared transitions at wavelengths between 700&nbsp;nanometers and 900&nbsp;nanometers. In 1950, [[Aden Meinel]] showed that these were transitions of the hydroxyl molecule, OH.<ref>{{cite journal 
| vauthors = Meinel AB |title=OH Emission Bands in the Spectrum of the Night Sky. I |journal=Astrophysical Journal |volume=111 |pages=555–564 |year=1950 |doi=10.1086/145296 |doi-access=free |bibcode=1950ApJ...111..555M |bibcode-access=free |url=http://articles.adsabs.harvard.edu/pdf/1950ApJ...111..555M |url-status=live |archive-url= https://web.archive.org/web/20221024073717/https://articles.adsabs.harvard.edu/pdf/1950ApJ...111..555M |archive-date= Oct 24, 2022 }}</ref>

===Surface of the Moon===
In 2009, India's [[Chandrayaan-1]] satellite and the [[NASA|National Aeronautics and Space Administration (NASA)]] [[Cassini spacecraft]] and [[Deep Impact probe]] each detected evidence of water by evidence of hydroxyl fragments on the [[Moon]]. As reported by Richard Kerr, "A [[spectrometer]] [the Moon Mineralogy Mapper, also known as "M3"] detected an infrared absorption at a wavelength of 3.0&nbsp;micrometers that only water or hydroxyl—a hydrogen and an oxygen bound together—could have created."<ref>{{cite web | vauthors = Kerr RA |url= https://www.science.org/content/article/whiff-water-found-moon |title=A Whiff of Water Found on the Moon |publisher=Science |date=24 September 2009 |access-date=2016-06-01 |url-status=live |archive-url= https://web.archive.org/web/20231208174247/https://www.science.org/content/article/whiff-water-found-moon |archive-date=Dec 8, 2023 }}</ref> [[NASA]] also reported in 2009 that the [[LCROSS]] probe revealed an [[ultraviolet]] emission spectrum consistent with hydroxyl presence.<ref name=nasa>{{cite web |url=http://www.nasa.gov/mission_pages/LCROSS/main/prelim_water_results.html |title=LCROSS Impact Data Indicates Water on Moon | vauthors = Dino J |date=13 November 2009 |access-date=2009-11-14 |publisher=[[NASA]] |url-status=dead |archive-url=https://web.archive.org/web/20091115071128/http://www.nasa.gov/mission_pages/LCROSS/main/prelim_water_results.html |archive-date=2009-11-15 }}</ref>

On 26 October 2020, [[NASA]] reported definitive evidence of water on the sunlit surface of the Moon, in the vicinity of the crater [[Clavius|Clavius (crater)]], obtained by the [[Stratospheric Observatory for Infrared Astronomy | Stratospheric Observatory for Infrared Astronomy (SOFIA)]].<ref>{{cite journal | vauthors = Honniball CI, Lucey PG, Li S, Shenoy S, Orlando TM, Hibbitts CA, Hurley DM, Farrell WM |title=Molecular water detected on the sunlit Moon by SOFIA|journal=Nature Astronomy |year= 2020 |volume=5 |issue=2 |pages=121–127 |doi=10.1038/s41550-020-01222-x |bibcode=2021NatAs...5..121H |s2cid=228954129}}</ref> The SOFIA Faint Object infrared Camera for the SOFIA Telescope (FORCAST) detected emission bands at a wavelength of 6.1&nbsp;micrometers that are present in water but not in hydroxyl. The abundance of water on the Moon's surface was inferred to be equivalent to the contents of a 12-ounce bottle of water per cubic meter of lunar soil.<ref>{{cite web |url=https://www.nasa.gov/press-release/nasa-s-sofia-discovers-water-on-sunlit-surface-of-moon/ |title=NASA's SOFIA Discovers Water on Sunlit Surface of Moon | vauthors = Chou F, Hawkes A |date=26 October 2020 |access-date=2020-10-26 |publisher=[[NASA]]}}</ref>

The [[Chang'e 5]] probe, which landed on the Moon on 1 December 2020, carried a mineralogical spectrometer that could measure infrared reflectance spectra of lunar rock and regolith. The reflectance spectrum of a rock sample at a wavelength of 2.85&nbsp;micrometers indicated localized water/hydroxyl concentrations as high as 180 parts per million.<ref>{{cite journal | vauthors = Lin H, Li S, Xu R, Liu Y, Wu X, Yang W, Wei Y, Lin Y, He Z, Hui H, He K, Hu S, Zhang C, Li C, Lv G, Yuan L, Zou Y, Wang C |title=In situ detection of water on the Moon by the Chang'E-5 lander|journal=Science Advances |year= 2022 |volume=8 |issue=1|pages=eabl9174 |doi=10.1126/sciadv.abl9174|pmid=34995111|pmc=8741181|bibcode=2022SciA....8.9174L}}</ref>

===Atmosphere of Venus===
The [[Venus Express]] orbiter collected [[Venus]] science data from April 2006 until December 2014. In 2008, Piccioni, ''et al.'' reported measurements of night-side airglow emission in the atmosphere of Venus made with the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express. They attributed emission bands in wavelength ranges of 1.40–1.49&nbsp;micrometers and 2.6–3.14 micrometers to vibrational transitions of OH.<ref name="Piccioni Drossart Zasova Migliorini 2008 pp. L29–L33">{{cite journal |last1=Piccioni |first1=G. |last2=Drossart |first2=P. |last3=Zasova |first3=L. |last4=Migliorini |first4=A. |last5=Gérard |first5=J.-C. |last6=Mills |first6=F. P. |last7=Shakun |first7=A. |last8=García Muñoz |first8=A. |last9=Ignatiev |first9=N. |last10=Grassi |first10=D. |last11=Cottini |first11=V. |last12=Taylor |first12=F. W. |last13=Erard |first13=S. |title=First detection of hydroxyl in the atmosphere of Venus |journal=Astronomy & Astrophysics |publisher=EDP Sciences |volume=483 |issue=3 |date=2008-04-01 |issn=0004-6361 |doi=10.1051/0004-6361:200809761 |pages=L29–L33|doi-access=free |bibcode=2008A&A...483L..29P |hdl=1885/35639 |hdl-access=free }}</ref> This was the first evidence for OH in the atmosphere of any planet other than Earth.<ref name="Piccioni Drossart Zasova Migliorini 2008 pp. L29–L33"/>

===Atmosphere of Mars===
In 2013, OH near-infrared spectra were observed in the night glow in the polar winter atmosphere of Mars by use of the [[Compact Reconnaissance Imaging Spectrometer for Mars]] (CRISM).<ref>{{cite journal | vauthors = Clancy RT, Sandor BJ, García-Muñoz A, Lefèvre F, Smith MD, Wolff MJ, Montmessin F, Murchie SL, Nair H |title=First detection of Mars atmospheric hydroxyl: CRISM Near-IR measurement versus LMD GCM simulation of OH Meinel band emission in the Mars polar winter atmosphere |journal=Icarus |volume=226 |pages=272–281 |year=2013 |issue=1 |doi=10.1016/j.icarus.2013.05.035 |bibcode=2013Icar..226..272T }}
</ref>

===Exoplanets===
In 2021, evidence for OH in the dayside atmosphere of the exoplanet [[WASP-33b]] was found in its emission spectrum at wavelengths between 1 and 2 micrometers.<ref>{{cite journal |author=Stevanus K. Nugroho |author2=Hajime Kawahara |author3=Neale P. Gibson |author4=Ernst J. W. de Mooij |author5=Teruyuki Hirano |author6=Takayuki Kotani |author7=Yui Kawashima |author8=Kento Masuda |author9=Matteo Brogi |author10=Jayne L. Birkby |author11=Chris A. Watson |author12=Motohide Tamura |author13=Konstanze Zwintz |author14=Hiroki Harakawa |author15=Tomoyuki Kudo |author16=Masayuki Kuzuhara |author17=Klaus Hodapp |author18=Masato Ishizuka |author19=Shane Jacobson |author20=Mihoko Konishi |author21=Takashi Kurokawa |author22=Jun Nishikawa |author23=Masashi Omiya |author24=Takuma Serizawa |author25=Akitoshi Ueda |author26=Sébastien Vievard |title=First Detection of Hydroxyl Radical Emission from an Exoplanet Atmosphere: High-dispersion Characterization of {WASP}-33b Using Subaru/{IRD} |journal=Astrophysical Journal Letters |volume=910 |pages=L9 |year=2021 |issue=1 |doi=10.3847/2041-8213/abec71 |s2cid=232110452 |url=https://pureadmin.qub.ac.uk/ws/files/237491214/2103.03094v1.pdf |doi-access=free }}</ref> Evidence for OH in the atmosphere of exoplanet [[WASP-76b]] was subsequently found.<ref>{{cite journal |author=R. Landman |author2=A. Sánchez-López |author3=P. Mollière |author4=A. Y. Kesseli |author5=A. J. Louca |author6=I. A. G. Snellen |title=Detection of OH in the ultra-hot Jupiter WASP-76b
 |journal=Astronomy and Astrophysics |volume=656 |pages=A119 |year=2021 |issue=1 | doi = 10.1051/0004-6361/202141696  |doi-access=free |arxiv=2110.11946
 |bibcode=2021A&A...656A.119L
 |s2cid=239616465}}</ref> Both [[WASP-33b]] and [[WASP-76b]] are [[ultra-hot Jupiters]] and it is likely that any water in their atmospheres is present as dissociated ions.