Online Encyclopedia
Adrastea (moon)
Discovery | |||||||
---|---|---|---|---|---|---|---|
Discovered by |
David C. Jewitt G. Edward Danielson |
||||||
Discovered on | July 8 1979 | ||||||
Orbital characteristics | |||||||
Mean radius | 129,000 km | ||||||
Eccentricity | 0.0018 | ||||||
Revolution period | 7h 9.5m | ||||||
Inclination | 0.05° | ||||||
Is a satellite of | Jupiter | ||||||
Physical characteristics | |||||||
Mean diameter | 16.4 km | ||||||
Surface area | km2 | ||||||
Mass | 1.8894×1016 kg | ||||||
Mean density | 4.5 g/cm3 | ||||||
Surface gravity | 0.012 m/s2 | ||||||
Surface Gravity (Earth = 1) |
0.00122 | ||||||
Rotation period | 7h 9.5m | ||||||
Axial tilt | 0° | ||||||
Albedo | 0.05 | ||||||
Surface temp. |
|
||||||
Atmospheric pressure | 0 kPa |
Adrastea ("a DRAS tee a") is the second of Jupiter's known moons (counting outward from the planet). It was discovered on Voyager 2 probe photographs taken in 1979 and received the designation S/1979 J 1 (IAUC 3454) after the discovery had been announced in Science (vol. 206, p. 951, November 23, 1979). In 1983 it was officially named after the mythological Adrastea, daughter of Jupiter and Ananke.
It belongs to the Amalthea group of small inner jovian moons.
Adrastea is inside Jupiter's planetary ring and may be the source of some of its material. Its orbit lies inside Jupiter's synchronous orbit radius, and as a result tidal forces are slowly causing its orbit to decay. It is also within Jupiter's Roche limit, but is small enough to avoid tidal disruption.
Jupiter |
---|
Amalthea group | Io | Europa | Ganymede | Callisto | Themisto | Himalia group | S/2003 J 20 |
S/2003 J 12 | Ananke group | Carme group | Pasiphaė group | S/2003 J 2 |
(see also: Jupiter's natural satellites) |