木卫五的密度小于水的密度。

Amalthea's density is less than that of water.

作者信息

Anderson John D, Johnson Torrence V, Schubert Gerald, Asmar Sami, Jacobson Robert A, Johnston Douglas, Lau Eunice L, Lewis George, Moore William B, Taylor Anthony, Thomas Peter C, Weinwurm Gudrun

机构信息

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA.

出版信息

Science. 2005 May 27;308(5726):1291-3. doi: 10.1126/science.1110422.

DOI:10.1126/science.1110422

PMID:15919987

Abstract

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.

摘要

2002年11月5日，伽利略号航天器与木星内侧小卫星之一阿玛尔忒亚相遇时获取的射电多普勒数据得出其质量为(2.08±0.15)×10¹⁸千克。1979年两艘旅行者号航天器拍摄的阿玛尔忒亚图像以及1996年11月至1997年6月伽利略号拍摄的图像得出其体积为(2.43±0.22)×10⁶立方千米。因此，该卫星的密度为每立方米857±99千克。我们认为阿玛尔忒亚是多孔的，由水冰以及岩石物质构成，因而形成于太阳系的寒冷区域，可能并非在其目前靠近木星的位置。