熱クロノメトリーによって明らかにされたH-コンドライト母小惑星の構造と熱史
Mario Trieloff1, Elmar K Jessberger, Ingrid Herrwerth
1Mineralogisches Institut der Universität Heidelberg, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany. trieloff@min.uni-heidelberg.de
Nature
|April 4, 2003
まとめ
Hコンドライトのような初期の太陽系惑星系は,アルミニウム-26の腐敗による内部加熱によって急速に形成された可能性が高い. これにより,数百万年にわたって冷却された層状の親体が形成され,中央地域はより高い温度を経験し,外層よりも冷却が遅い.
科学分野:
- 惑星科学は惑星科学である.
- 宇宙化学 (コスモケミストリー)
- ジオクロノロジー (Geochronology) について
背景:
- 初期の太陽系は46億年前に分子雲から形成されました.
- 小惑星の形成は,1000万年以内に急速に起こった.
- 隕石の親体の熱史と熱源は議論されている.
研究 の 目的:
- Hコンドライトの親体の熱史と冷却を調査する.
- 区別されていない隕石の変形の原因となる熱源を決定する.
- 初期の惑星系の構造と冷却速度を再構築する.
主な方法:
- 244Pu核分裂軌道の熱クロノロジーを利用しました.
- 従業員 40Ar-39Ar 熱クロノロジー.
- 推定単一親体の未衝撃のHコンドライトを分析した.
主要な成果:
- 証拠は,26Alの腐敗から,内部加熱が続く急速な増殖を示唆しています.
- 親体は,明確な熱グラデーションを持つ層構造を開発した.
- 外部地域はより速く冷却され,中央地域よりも低い温度に達しました.
- 中部地域では,約1億6000万年かけて冷却され,390K°Cに達した.
結論:
- Hコンドライト変異の熱源は,おそらく26Alの腐敗であった.
- 蓄積と分化は,太陽系初期に急速な過程であった.
- 冷却歴は,長期間冷却した層状の親体構造を示しています.
関連する概念動画
Conditions on Early Earth
103.3K
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
103.3K
Diversity of Archaea IV
594
Hyperthermophilic archaea are a group of extremophiles thriving at temperatures above 80°C, often in hydrothermal vents and volcanic soils where conditions surpass the boiling point of water. At such temperatures, proteins, membranes, and DNA in most organisms degrade, but hyperthermophiles have evolved remarkable adaptations to maintain stability and function.Unique Cellular FeaturesHyperthermophilic membranes are composed of a monolayer of biphytanyl tetraether lipids, which resist...
594
Diversity of Archaea III
435
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like...
435
Diversity of Archaea I
847
Archaea, a domain of single-celled microorganisms, are classified into five major phyla based on genetic and biochemical characteristics: Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota. Among these, the phylum Euryarchaeota is notable for its remarkable diversity in morphology, metabolism, and ecological adaptations.Morphological and Metabolic DiversityMembers of Euryarchaeota exhibit a variety of cellular shapes, including rods and cocci. Their metabolic pathways...
847
Global Climate Change
29.7K
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
29.7K
Conditions on Early Earth
2.9K
No description available
2.9K


