Io (moon)
English: Io (moon)

Io
True-color image taken by the Galileo orbiter
Galileo spacecraft true-color image of Io. The dark spot just left of the center is the erupting volcano Prometheus. The whitish plains on either side of it are coated with volcanically deposited sulfur dioxide frost, whereas the yellower regions contain a higher proportion of sulfur.
Discovery
Discovered byGalileo Galilei
Discovery date8 January 1610
Designations
Pronunciation/[1]
Jupiter I
AdjectivesIonian
Orbital characteristics
Periapsis420000 km (0.002807 AU)
Apoapsis423400 km (0.002830 AU)
Mean orbit radius
421700 km (0.002819 AU)
Eccentricity0.0041
1.769137786 d (152853.5047 s, 42.45930686 h)
17.334 km/s
Inclination0.05° (to Jupiter's equator)
2.213° (to the ecliptic)
Satellite ofJupiter
Physical characteristics
Dimensions3,660.0 × 3,637.4 × 3,630.6 km[2]
Mean radius
1821.6±0.5 km (0.286 Earths)[3]
41910000 km2 (0.082 Earths)
Volume2.53×1010 km3 (0.023 Earths)
Mass(8.931938±0.000018)×1022 kg (0.015 Earths)[3]
Mean density
3.528±0.006 g/cm3[3]
1.796 m/s2 (0.183 g)
Moment of inertia factor
0.3755±0.0045[4] (estimate)
2.558 km/s
synchronous
Equatorial rotation velocity
271 km/h
Albedo0.63±0.02[3]
Surface temp.minmeanmax
Surface90 K110 K130 K[6]
5.02 (opposition)[5]
Atmosphere
Surface pressure
5 to 40 nbar
Composition by volume90% sulfur dioxide

Io is a moon of the planet Jupiter. It is Jupiter's third biggest moon with a diameter of 3642 km, being slightly bigger than Earth's moon. Io has about 400 active volcanos.

Io is the most volcanically active body in the Solar System. Volcanoes erupt massive volumes of silicate lava, sulphur and sulphur dioxide, constantly changing Io's appearance. This new basemap of Jupiter's moon Io was produced by combining the best images from both the Voyager 1 and Galileo Missions. Although the subjovian hemisphere of Io was poorly seen by Galileo, superbly detailed Voyager 1 images cover longitudes from 240 W to 40 W and the nearby southern latitudes.

Due to the same tidal locking that makes the Moon have the same side always facing Earth, Io always has the same side facing Jupiter. Unlike most celestial bodies, Io is a prolate spheroid, pulled out of round by tidal stress from Jupiter’s gravity.

  • references

References

  1. EYE-oh, or as Greek: Ἰώ
  2. Thomas, P. C. (1998). "The Shape of Io from Galileo Limb Measurements". Icarus 135 (1): 175–180. 10.1006/icar.1998.5987. 
  3. 3.0 3.1 3.2 3.3 Yeomans, Donald K. (13 July 2006). "Planetary Satellite Physical Parameters". JPL Solar System Dynamics.
  4. Showman, Adam P.; Malhotra, Renu (October 1999). "The Galilean Satellites". Science 286 (5437): 77–84. 10.1126/science.286.5437.77. 10506564. 
  5. "Classic Satellites of the Solar System". Observatorio ARVAL. Archived from the original on 25 August 2011. Retrieved 28 September 2007.
  6. Rathbun, J. A.; Spencer, J.R.; Tamppari, L.K.; Martin, T.Z.; Barnard, L.; Travis, L.D. (2004). "Mapping of Io's thermal radiation by the Galileo photopolarimeter-radiometer (PPR) instrument". Icarus 169 (1): 127–139. 10.1016/j.icarus.2003.12.021. 
Other Languages
Afrikaans: Io (maan)
Alemannisch: Io (Mond)
العربية: آيو (قمر)
asturianu: Ío (lluna)
azərbaycanca: İo
تۆرکجه: آیو (قمر)
Bân-lâm-gú: Io (oē-chheⁿ)
беларуская: Іо (спадарожнік)
беларуская (тарашкевіца)‎: Іё (спадарожнік Юпітэра)
български: Йо (спътник)
bosanski: Ija (satelit)
brezhoneg: Io (loarenn)
Чӑвашла: Ио (спутник)
čeština: Io (měsíc)
corsu: Io
Cymraeg: Io (lloeren)
dansk: Io (måne)
Deutsch: Io (Mond)
eesti: Io (kuu)
Ελληνικά: Ιώ (δορυφόρος)
English: Io (moon)
español: Ío (satélite)
Esperanto: Ioo (luno)
euskara: Io
فارسی: آیو (قمر)
français: Io (lune)
Gaeilge: Io (gealach)
galego: Ío (lúa)
한국어: 이오 (위성)
հայերեն: Իո (արբանյակ)
हिन्दी: आयो (उपग्रह)
hrvatski: Ija (mjesec)
Bahasa Indonesia: Io (satelit)
íslenska: Íó (tungl)
italiano: Io (astronomia)
עברית: איו (ירח)
ქართული: იო
қазақша: Ио (серік)
Кыргызча: Ио
latviešu: Jo (pavadonis)
Lëtzebuergesch: Io (Mound)
лезги: Ио
lietuvių: Ijo (palydovas)
magyar: Ió (hold)
македонски: Ија (месечина)
മലയാളം: അയോ
Bahasa Melayu: Io (bulan)
Mìng-dĕ̤ng-ngṳ̄: Io (ôi-sĭng)
Mirandés: Io
монгол: Ио (дагуул)
Nederlands: Io (maan)
日本語: イオ (衛星)
norsk: Io (måne)
norsk nynorsk: Jupitermånen Io
occitan: Io (luna)
پنجابی: آئیو
Plattdüütsch: Io (Maand)
português: Io (satélite)
română: Io (satelit)
русский: Ио (спутник)
Scots: Io (muin)
sicilianu: Io (satèlliti)
සිංහල: අයෝ
سنڌي: آيو
slovenčina: Io (mesiac)
slovenščina: Io (luna)
српски / srpski: Ија (сателит)
srpskohrvatski / српскохрватски: Io (mjesec)
suomi: Io (kuu)
svenska: Io (måne)
Tagalog: Io (buwan)
татарча/tatarça: Ио (иярчен)
тоҷикӣ: Ио (радиф)
Türkçe: İo (uydu)
українська: Іо (супутник)
Tiếng Việt: Io (vệ tinh)
文言: 木衛一
Winaray: Io (bulan)
吴语: 木卫一
粵語: 木衛一
中文: 木卫一