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Updated: Jul 13, 2026

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Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures
Published on: June 28, 2017
アマルテアの密度は水の密度より小さい
John D Anderson1, Torrence V Johnson, Gerald Schubert
1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA. john.d.anderson@jpl.nasa.gov
まとめ
ガリレオ宇宙船のデータは,木星の衛星アマルテアが密度が低いことを明らかにし,それが多孔性であり,氷と岩で構成されていることを示唆しています. これは,アマルテア星が太陽系の寒い地域で形成された可能性があることを示しています.
科学分野:
- 惑星科学は惑星科学である.
- 天体物理学 天体物理学
- 太陽系探査 太陽系探査について
背景:
- アマルテア (Amalthea) は木星の小さな内側衛星の1つである.
- 小さな衛星の構成と起源を理解することで,太陽系形成の洞察が得られます.
研究 の 目的:
- アマルテアの質量,体積,密度を測定する.
- アマルテアの構成と形成場所を推論する.
主な方法:
- ガリレオ宇宙船がアマルテアと遭遇した時のラジオドップラーデータ.
- ヴォイジャーとガリレオの宇宙船からの画像の分析.
主要な成果:
- アマルテアの質量は (2.08 +/- 0.15) x 10 ^ 18 kg と決定されました.
- 容量は (2.43 +/- 0.22) x 10^6 km^3.3 として計算されました.
- アマルテアの密度は857 +/- 99 kg/m^3.3であることが判明しました.
結論:
- アマルテアの低密度は,それが多孔性であり,水氷と岩石の材料で構成されていることを示唆しています.
- この組成は,アマルテアが太陽系の寒い地域で形成された可能性が高いことを示しており,現在の位置ではない可能性があります.
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