Observation of electromagnetic radiation at ultraviolet wavelengths
Ultraviolet astronomy is the observation of
electromagnetic radiation at
ultraviolet wavelengths between approximately 10 and 320
nanometres; shorter wavelengths—higher energy photons—are studied by
X-ray astronomy and
gamma-ray astronomy.[1] Ultraviolet light is not visible to the
human eye.[2] 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.[1]
Overview
Ultraviolet
line spectrum measurements (
spectroscopy) are used to discern the chemical composition, densities, and temperatures of the
interstellar medium, and the temperature and composition of hot young stars. UV observations can also provide essential information about the
evolution of galaxies. They can be used to discern the presence of a hot
white dwarf or
main sequence companion in orbit around a cooler star.[3][4]
The ultraviolet
universe looks quite different from the familiar
stars and
galaxies seen in
visible light.
Most stars are actually relatively cool objects emitting much of their electromagnetic radiation in the visible or near-
infrared part of the spectrum. Ultraviolet radiation is the signature of hotter objects, typically in the early and late stages of their
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
Milky Way.
Space-based solar observatories such as
SDO and
SOHO use ultraviolet telescopes (called
AIA and
EIT, respectively) to view activity on the Sun and its
corona. Weather satellites such as the
GOES-R series also carry
telescopes for observing the Sun in ultraviolet.
^Reimers, D. (July 1984). "Discovery of a white dwarf companion of the "hybrid" K giant HD 81817". Astronomy and Astrophysics. 136: L5–L6.
Bibcode:
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^Ortiz, Roberto; Guerrero, Martín A. (September 2016). "Ultraviolet emission from main-sequence companions of AGB stars". Monthly Notices of the Royal Astronomical Society. 461 (3): 3036–3046.
arXiv:1606.09086.
Bibcode:
2016MNRAS.461.3036O.
doi:
10.1093/mnras/stw1547.
^Lampton, M., Sasseen, T. P., Wu, X., & Bowyer, S. (1993). "A study of the impact of the space shuttle environment on faint far-UV geophysical and astronomical phenomena". Geophysical Research Letters. 20 (6): 539–542.
Bibcode:
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doi:
10.1029/93GL00093.{{
cite journal}}: CS1 maint: multiple names: authors list (
link)