Amalthea's density is less than that of water.
Radio Doppler data from the Galileo spacecraft's encounter with Amalthea, one of Jupiter's small inner moons, on 5 November 2002 yield a mass of (2.08 +/- 0.15) x 10(18) kilograms. Images of Amalthea from two Voyager spacecraft in 1979 and Galileo imaging between November 1996 and June 1997 yield a volume of (2.43 +/- 0.22) x 10(6) cubic kilometers. The satellite thus has a density of 857 +/- 99 kilograms per cubic meter. We suggest that Amalthea is porous and composed of water ice, as well as rocky material, and thus formed in a cold region of the solar system, possibly not at its present location near Jupiter.
Anderson
John D
JD
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA. john.d.anderson@jpl.nasa.gov
Johnson
Torrence V
TV
Schubert
Gerald
G
Asmar
Sami
S
Jacobson
Robert A
RA
Johnston
Douglas
D
Lau
Eunice L
EL
Lewis
George
G
Moore
William B
WB
Taylor
Anthony
A
Thomas
Peter C
PC
Weinwurm
Gudrun
G
D006112:Gravitation; D007053:Ice; D018538:Jupiter; D011312:Pressure; D018531:Spacecraft; D014867:Water
D007053:Ice; D014867:Water