Image of Adrastea taken by Galileo's solid state imaging system between November 1996 and June 1997.
|Discovered by||David C. Jewitt
G. Edward Danielson
|Discovery date||July 8, 1979|
|Mean orbit radius||129,000 km|
|Orbital period||0.29826 d (7 h 9.5 min)|
|Average orbital speed||31.378 km/s|
|Inclination||0.03° (to Jupiter's equator)|
|Mean radius||8.2 ± 2.0 km|
|Mean density||0.86 g/cm³ (assumed)|
|Equatorial surface gravity||~0.002 m/s² (0.0004 g)|
|Escape velocity||~0.008 km/s|
Adrastea or Jupiter XV, is the second closest moon to Jupiter. It was found by David C. Jewitt and G. Edward Danielson in Voyager 2 probe photographs taken in 1979 and received the designation S/1979 J 1. In 1983, it was named after the mythological Adrastea, who was a daughter of Jupiter and Ananke.
Adrastea was the first moon to be found from images taken by an interplanetary spacecraft, rather than through telescopic photography.
Physical characteristics [change]
Adrastea is non-spherical and measures 20x16x14 km³ across. What Adrastea is made of and the mass of Adrastea are not known, but assuming that its mean density is like that of Amalthea (~0.86 g/cm³) its mass can be estimated at ~2×1015 kg. Amalthea's density implies that moon is composed of water ice with a porosity of 10-15%, and Adrastea may be similar.
No surface details of Adrastea are known, due to the low resolution of available images.
Adrastea is the smallest and second closest member of the closer moons to Jupiter. It orbits Jupiter at ~129,000 km (1.806 Jupiter radii) within the planet's Main Ring. The orbit has very small eccentricity ~0.0015 and inclination ~ 0.03° relative to the equator of Jupiter.
- Evans, M.W.; Porco, C.C.; Hamilton, D.P. (2002). "The Orbits of Metis and Adrastea: The Origin and Significance of their Inclinations". Bulletin of the American Astronomical Society 34: 883. http://adsabs.harvard.edu/abs/2002DPS....34.2403E.
- Burns, J.A.; D.P. Simonelli & M.R. Showalter et al. (2004), "Jupiter’s Ring-Moon System", in Bagenal, F.; Dowling, T. E.; McKinnon, W. B., Jupiter: The planet, Satellites and Magnetosphere, Cambridge University Press
- Calculated on the basis of other parameters
- Thomas, P.C.; Burns, J.A.; Rossier, L.; et al. (1998). "The Small Inner Satellites of Jupiter". ICARUS 135: 360–371. doi:10.1006/icar.1998.5976. http://adsabs.harvard.edu/abs/2000Icar..147..353S.
- IAUC 3454: Editorial Notice 1980 February 25 (discovery)
- Jewitt, D.C.; Danielson, G.E.; Synnott, S.P. (1979). "Discovery of a New Jupiter Satellite". Science 206: 951. http://links.jstor.org/sici?sici=0036-8075%2819791123%293206:4421%3c951:DOANJS%3e2.0.CO%3b2-V&origin=ads.
- IAUC 3872: Satellites of Jupiter and Saturn 1983 September 30 (naming the moon)
- Anderson, J.D.; Johnson, T.V.; Shubert, G.; et al. (2005). "Amalthea’s Density Is Less Than That of Water". Science 308: 1291–1293. doi:10.1126/science.1110422. http://adsabs.harvard.edu/abs/2005Sci...308.1291A.
Other websites [change]