Jupiter XV - 1979J1


Adrastea [a-DRAS-tee-uh] is the second innermost known satellite of Jupiter. Adrastea was the daughter of Jupiter and Ananke and the distributor of rewards and punishments. Adrastea and Metis lie within Jupiter's main ring and may be the source of material for the ring. Very little is known about Adrastea.

Adrastea Statistics
 Discovered byD. Jewitt & E. Danielson 
 Date of discovery1979 
 Mass (kg)1.91e+16 
 Mass (Earth = 1)3.1961e-09 
 Radius (km)12.5x10x7.5 
 Radius (Earth = 1)1.9599e-03 
 Mean density (gm/cm^3)4.5 
 Mean distance from Jupiter (km)128,971 
 Rotational period (days)
 Orbital period (days)0.298260 
 Mean orbital velocity (km/sec)31.45 
 Orbital eccentricity0.0000 
 Orbital inclination (degrees)0.0000 
 Escape velocity (km/sec)0.0143 
 Visual geometric albedo0.05 
 Magnitude (Vo)19.1 

Views of Adrastea

Discovery Image
This is the discovery image (FDS 20630.53) of Adrastea. It was taken by the Voyager spacecraft 23 hours before the closest approach to Jupiter. This image is a wide angle picture taken with a 15 second exposure. The range is 1.4 x 106 km. The faint line is the Jovian ring. Adrastea is a small dot above the arrow. The brighter dot to the left is a star. (Credit: Calvin J. Hamilton)

Subsequent Observation
This image (FDS 20630.48) of Adrastea was taken 5 minutes earlier than the previous image. The exposure time was 96 seconds. The faint band is the Jovian ring and is smeared because of parallax and spacecraft motion. Adrastea is the bright line in the lower right. A star can be seen as a line in the upper left. Notice the difference in length and direction of the two lines. This image was used to verify that the spot in the previous image was indeed a satellite of Jupiter. (Credit: Calvin J. Hamilton)


Jewitt, David C. et al. "Discovery of a New Jupiter Satellite." Science, Vol 206, 23 November 1979.

Synnott, S. P. "Orbits of the Small Inner Satellites of Jupiter." Icarus 58, 1984.


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Copyright © 1997 by Calvin J. Hamilton. All rights reserved.