View source for Astronomy:Ultraviolet astronomy

{{short description|Observation of electromagnetic radiation at ultraviolet wavelengths}}
[[Image:M81 wide Galex.jpg|thumb|A GALEX image of the [[Spiral galaxy|spiral galaxy]] Messier 81 in ultraviolet light.  Credit:GALEX/NASA/JPL-Caltech.]]

'''Ultraviolet astronomy''' is the observation of [[Physics:Electromagnetic radiation|electromagnetic radiation]] at [[Physics:Ultraviolet|ultraviolet]] wavelengths between approximately 10 and 320 [[Nanometre|nanometre]]s; shorter wavelengths&mdash;higher energy photons&mdash;are studied by [[Astronomy:X-ray astronomy|X-ray astronomy]] and [[Astronomy:Gamma-ray astronomy|gamma-ray astronomy]].<ref name="cox2000">{{cite book
  | editor=A. N. Cox
  | title=Allen's Astrophysical Quantities
  | date=2000
  | publisher=Springer-Verlag
  | location=New York
  | isbn=0-387-98746-0}}</ref> Ultraviolet light is not visible to the [[Biology:Human eye|human eye]].<ref>{{cite web|url=https://science.ksc.nasa.gov/mirrors/msfc/description/ultraviolet.html|title=Ultraviolet Light|archive-url=https://web.archive.org/web/20170213163854/https://science.ksc.nasa.gov/mirrors/msfc/description/ultraviolet.html|archive-date=2017-02-13|access-date=2017-02-12}}</ref> Most of the light at these wavelengths is absorbed by the Earth's atmosphere, so observations at these wavelengths must be performed from the upper atmosphere or from space.<ref name="cox2000"/>

==Overview==
Ultraviolet [[Physics:Spectral line|line spectrum]] measurements ([[Physics:Astronomical spectroscopy|spectroscopy]]) are used to discern the chemical composition, densities, and temperatures of the [[Astronomy:Interstellar medium|interstellar medium]], and the temperature and composition of hot young stars. UV observations can also provide essential information about the [[Astronomy:Galaxy formation and evolution|evolution of galaxies]]. They can be used to discern the presence of a hot [[Astronomy:White dwarf|white dwarf]] or [[Astronomy:Main sequence|main sequence]] companion in orbit around a cooler star.<ref name=Reimers1984/><ref name=Ortiz2016/>

The ultraviolet [[Astronomy:Universe|universe]] looks quite different from the familiar [[Astronomy:Star|star]]s and [[Astronomy:Galaxy|galaxies]] seen in [[Physics:Visible light|visible light]].
Most stars are actually relatively cool objects emitting much of their electromagnetic radiation in the visible or near-[[Physics:Infrared|infrared]] part of the spectrum. Ultraviolet radiation is the signature of hotter objects, typically in the early and late stages of their [[Astronomy:Stellar evolution|evolution]]. In the Earth's sky seen in ultraviolet light, most stars would fade in prominence. Some very young massive stars and some very old stars and galaxies, growing hotter and producing higher-energy radiation near their birth or death, would be visible. Clouds of gas and dust would block the vision in many directions along the [[Astronomy:Milky Way|Milky Way]].

Space-based solar observatories such as [[Astronomy:Solar Dynamics Observatory|SDO]] and [[Astronomy:Solar and Heliospheric Observatory|SOHO]] use ultraviolet telescopes (called [[Astronomy:Solar Dynamics Observatory#Atmospheric Imaging Assembly (AIA)|AIA]] and [[Astronomy:Extreme ultraviolet Imaging Telescope|EIT]], respectively) to view activity on the Sun and its [[Physics:Solar corona|corona]]. Weather satellites such as the [[Engineering:Geostationary Operational Environmental Satellite|GOES-R]] series also carry [[Engineering:GOES-16#Sun-facing|telescopes]] for observing the Sun in ultraviolet.

The [[Astronomy:Hubble Space Telescope|Hubble Space Telescope]] and [[Astronomy:Far Ultraviolet Spectroscopic Explorer|FUSE]] have been the most recent major [[Astronomy:Space telescope|space telescope]]s to view the near and far UV [[Physics:Electromagnetic spectrum|spectrum]] of the sky, though other UV instruments have flown on smaller observatories such as [[Astronomy:GALEX|GALEX]], as well as sounding rockets and the [[Engineering:Space Shuttle|Space Shuttle]].

Pioneers in ultraviolet astronomy include [[Biography:George Robert Carruthers|George Robert Carruthers]], Robert Wilson, and Charles Stuart Bowyer.
[[File:PIA20061 - Andromeda in High-Energy X-rays, Figure 1.jpg|thumb|center|500px|[[Astronomy:Andromeda Galaxy|Andromeda Galaxy]] - in high-energy X-ray and ultraviolet light (released 5 January 2016).]]

==Ultraviolet space telescopes==
[[File:M101 UIT.gif|thumb|Astro 2 UIT captures [[Astronomy:Pinwheel Galaxy|M101]] with ultraviolet shown in purple]]
*{{flagicon|United States}} - Far Ultraviolet Camera/Spectrograph on [[Engineering:Apollo 16|Apollo 16]] (April 1972)
*{{flagicon|United States}} + ESRO - [[Astronomy:TD-1A|TD-1A]] (135-286&nbsp;nm; 1972–1974)
*{{flagicon|United States}} - [[Astronomy:Orbiting Astronomical Observatory|Orbiting Astronomical Observatory]] (#2:1968-73. #3:1972-1981)
*{{flagicon|Soviet Union}} - Orion 1 and Orion 2 Space Observatories (#1: 200-380&nbsp;nm, 1971; #2: 200-300&nbsp;nm, 1973)
*{{flagicon|United States}} + {{flagicon|Netherlands}} - [[Astronomy:Astronomical Netherlands Satellite|Astronomical Netherlands Satellite]] (150-330&nbsp;nm, 1974–1976)
*{{flagicon|United States}} + {{flagicon|European Union}} - [[Astronomy:International Ultraviolet Explorer|International Ultraviolet Explorer]] (115-320&nbsp;nm, 1978–1996)
*{{flagicon|Soviet Union}} - [[Engineering:Astron (spacecraft)|Astron-1]] (150-350&nbsp;nm, 1983–1989)
*{{flagicon|Soviet Union}} - Glazar 1 and 2 on [[Astronomy:Mir|Mir]] (in [[Astronomy:Kvant-1|Kvant-1]], 1987–2001)
*{{flagicon|United States}} - FAUST (140-180 nm, in ATLAS-1 [[Astronomy:Spacelab|Spacelab]] aboard [[Engineering:STS-45|STS-45]] mission, March 1992)<ref>{{cite journal |author=Lampton, M., Sasseen, T. P., Wu, X., & Bowyer, S.|date=1993 |title=A study of the impact of the space shuttle environment on faint far-UV geophysical and astronomical phenomena |url= |journal=Geophysical Research Letters |volume= 20|issue=6 |pages=539–542|bibcode=1993GeoRL..20..539L |doi= 10.1029/93GL00093}}</ref>
*{{flagicon|United States}} - [[Astronomy:Extreme Ultraviolet Explorer|EUVE]] (7-76&nbsp;nm, 1992–2001)
*{{flagicon|United States}} - [[Astronomy:Far Ultraviolet Spectroscopic Explorer|FUSE]] (90.5-119.5&nbsp;nm, 1999–2007)
*{{flagicon|United States}} + {{flagicon|European Union}} - [[Astronomy:Extreme ultraviolet Imaging Telescope|Extreme ultraviolet Imaging Telescope]] (on [[Astronomy:Solar and Heliospheric Observatory|SOHO]] imaging Sun at 17.1, 19.5, 28.4, and 30.4&nbsp;nm)
*{{flagicon|United States}} + {{flagicon|European Union}} - [[Astronomy:Hubble Space Telescope|Hubble Space Telescope]] (various 115-800&nbsp;nm,1990-1997-) ([[Astronomy:Space Telescope Imaging Spectrograph|STIS]] 115–1030&nbsp;nm, 1997–) ([[Engineering:Wide Field Camera 3|WFC3]] 200-1700&nbsp;nm, 2009–)
*{{flagicon|United States}} - Swift Gamma-Ray Burst Mission (170–650&nbsp;nm, 2004- )
*{{flagicon|United States}} - [[Astronomy:Hopkins Ultraviolet Telescope|Hopkins Ultraviolet Telescope]] (flew in 1990 and 1995)
*{{flagicon|Germany}} - [[Astronomy:ROSAT|ROSAT]] XUV<ref>[http://iraf.noao.edu/iraf/ftp/iraf/conf/web/adass_proc/adass_95/staubertr/staubertr.html R. Staubert, H. Brunner,1 H.-C. Kreysing - The German ROSAT XUV Data Center and a ROSAT XUV Pointed Phase Source Catalogue (1996)]</ref> (17-210eV) (30-6&nbsp;nm, 1990–1999)
*{{flagicon|United States}} - [[Astronomy:Far Ultraviolet Spectroscopic Explorer|Far Ultraviolet Spectroscopic Explorer]] (90.5-119.5 nm, 1999–2007)
*{{flagicon|United States}} - [[Astronomy:GALEX|Galaxy Evolution Explorer]] (135–280&nbsp;nm, 2003–2012)
*{{flagicon|Japan}} - [[Engineering:Hisaki (satellite)|Hisaki]]  (130-530&nbsp;nm, 2013 -)
*{{flagicon|China}} - [[Astronomy:Chang'e 3#Lunar-based ultraviolet telescope (LUT)|Lunar-based ultraviolet telescope (LUT)]]  (on [[Astronomy:Chang'e 3|Chang'e 3]] lunar lander, 245-340 &nbsp;nm, 2013 -)
*{{flagicon|India}} - [[Astronomy:Astrosat|Astrosat]]  (130-530&nbsp;nm, 2015 -)
*{{flagicon|United States}} - [[Astronomy:Colorado Ultraviolet Transit Experiment|Colorado Ultraviolet Transit Experiment]] (CUTE) - (255-330 nm spectrograph, 2021- )
*{{flagicon|Germany}} - Public Telescope (PST)<ref>[http://www.spektrum.de/news/ein-privates-weltraumteleskope-fuer-amateure-und-profis/1352064 Ein privates Weltraumteleskope für Amateure und Profis] Spektrum DE. June 2015</ref> (100-180&nbsp;nm, Proposed 2015, EU funded study )
*{{flagicon|United States}} - Viewpoint-1 SpaceFab.US (200-950&nbsp;nm, Launch planned 2022)<ref>{{Cite web|url=http://www.spacefab.us/space-telescopes.html|title = Space Telescopes}}</ref>

See also [[Astronomy:List of space telescopes#Ultraviolet|List of ultraviolet space telescopes]]

==Ultraviolet instruments on planetary spacecraft==
*{{flagicon|United States}} - UVIS (''[[Astronomy:Cassini–Huygens|Cassini]]'') - 1997 (at Saturn from 2004 to 2017)
*{{flagicon|United States}} - MASCS (''[[Astronomy:MESSENGER|MESSENGER]]'') - 2004 (at Mercury from 2011 to 2015)
*{{flagicon|United States}} - Alice (''[[Astronomy:New Horizons|New Horizons]]'') - 2006 (Pluto flyby in 2015)
*{{flagicon|United States}} - [[Astronomy:UVS (Juno)|UVS (''Juno'')]] - 2011 (at Jupiter since 2016)
*{{flagicon|United States}} - IUVS ([[Astronomy:MAVEN|MAVEN]]) - 2013 (at Mars since 2014)

==See also==
*{{annotated link|Astronomy:Markarian galaxies}}
*{{annotated link|Astronomy:Pea galaxy}}

{{Clear}}

==References==
{{Reflist|refs=
<ref name=Reimers1984>{{cite journal
| title=Discovery of a white dwarf companion of the "hybrid" K giant HD 81817
| last=Reimers | first=D.
| journal=Astronomy and Astrophysics
| volume=136 | pages=L5–L6 | date=July 1984
| bibcode=1984A&A...136L...5R }}</ref>
<ref name=Ortiz2016>{{cite journal
| title=Ultraviolet emission from main-sequence companions of AGB stars
| last1=Ortiz | first1=Roberto | last2=Guerrero | first2=Martín A.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=461 | issue=3 | pages=3036–3046 | date=September 2016
| arxiv=1606.09086 | bibcode=2016MNRAS.461.3036O 
| doi=10.1093/mnras/stw1547 }}</ref>
}}

==External links==

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[[Category:Ultraviolet astronomy| ]]
[[Category:Astronomical imaging]]
[[Category:Astronomical sub-disciplines]]
[[Category:Ultraviolet radiation|Astronomy]]

{{Sourceattribution|Ultraviolet astronomy}}