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彗星67P/チュリュモフ・ゲラシメンコの重力場から見た均質な核
M Pätzold1, T Andert2, M Hahn1
1Rheinisches Institut für Umweltforschung an der Universität zu Köln, Abteilung Planetenforschung, 50931 Köln, Germany.
Nature
|February 5, 2016
まとめ
彗星67P/チュリュモフ・ゲラシメンコ
科学分野:
- 惑星科学
- 彗星科学
- 天体物理学
背景:
- 彗星の核は主に塵と水氷で構成されています
- 以前の研究では,低密度と高毛細度が示されましたが,重大な不確実性がありました.
- 彗星の核の正確な特徴は 太陽系の形成を理解するために重要です
研究 の 目的:
- 彗星67P/チュリュモフ・ゲラシメンコの核の質量,密度,多孔性,内部構造を正確に決定する.
- 彗星の組成と内部の性質の理解を深めるため
- 核内の空洞の均一性と存在を調査する.
主な方法:
- 彗星67P/チュリュモフ・ゲラシメンコの飛行中の宇宙船の速度乱射の分析.
- 核の重力場と点質量 (GM) の計算.
- 重力データと体積の推定を統合して,体積密度と多孔性を導き出します.
主要な成果:
- 正確な質量 (M = (9,982 ± 3) × 10^9 kg) と重力パラメータ (GM = 666.2 ± 0.2 m2/s2) を決定した.
- 平均体密度は533 ±6 kg/m3で,低密度で高孔性の体 (72-74%) を示しています.
- 組成量は氷の4倍の量と2倍の量と推定されています.
- 核の内部は均質で大きな空洞がないと推論されている.
結論:
- 彗星67P/チュリュモフ・ゲラシメンコの核は,非常に多孔性の低密度で,多塵の組成を持っています.
- 内部構造は地球規模で均質に見られていて 毛細さは物質の固有の特性であることを示唆しています
- これらの発見は,彗星の内部とその形成過程をよりよく理解するのに役立ちます.
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