彗星物質の同位体組成は,スターダストによって帰還される
Kevin D McKeegan1, Jerome Aléon, John Bradley
1Department of Earth and Space Sciences, University of California Los Angeles, Los Angeles, CA 90095-1567, USA. mckeegan@ess.ucla.edu
まとめ
彗星81P/ワイルド2は,純粋な太陽前物質ではなく,太陽系内側と外側の両方の物質を含んでいます. 同位体分析は起源の混合を明らかにし,純粋に原始的な彗星という考えに異議を唱える.
科学分野:
- 宇宙塵分析 コスミックダスト分析
- 彗星科学 彗星科学
- イソトープ地球化学 イソトープ地球化学
背景:
- 彗星は,初期の太陽系の残骸であり,その形成のヒントを提供します.
- 彗星81P/ワイルド2は,原始的な物質を潜在的に保存するユニークな組成のために研究されています.
研究 の 目的:
- 彗星81P/ワイルド2の粒子の断片の同位体組成を調べるために.
- 彗星内の物質の起源を特定し,その原始的な性質を評価する.
主な方法:
- 彗星の断片における水素,炭素,窒素,酸素の同位体組成物の分析.
- 個々の粒子の鉱物学および同位体シグネチャーの検査.
主要な成果:
- 同位体異質性は観察されましたが,極端な異常はまれで,限られたプレソラー物質を示唆しています.
- 非地上の窒素とネオン同位体は,原産の有機物質と揮発性物質の存在を示しています.
- ほとんどのシリケートと酸化物は太陽系の同位体起源を示し,一粒の耐火性粒子は16O濃縮を示し,太陽系内部の形成を示している.
結論:
- 彗星81P/ワイルド2は,プリソラー物質の原始的な集合体ではありません.
- 彗星には,太陽系の内側と外側の両方の材料の混合物が含まれています.
- 証拠によると,高温の太陽系内部の物質は,彗星が形成される前に,カイパーベルトに運ばれたという.
関連する概念動画
Classifying Matter by Composition
Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures.
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.
A mixture is composed of two or more types of...
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures.
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.
A mixture is composed of two or more types of...
Elements: Chemical Symbols and Isotopes
A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is used to indicate one atom of mercury (microscopic domain) or to label a container of many atoms of the element mercury (macroscopic domain).
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
Some symbols are derived from the common English name of the element; others are abbreviations of the name in another language — Latin, Greek or German. For example, the symbol for aluminum (common name)...
Electron Configuration of Multielectron Atoms
The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the 3s orbital, giving a 1s22s22p63s1 configuration. The electrons occupying the outermost shell orbital(s) (highest value of n) are called valence electrons, and those occupying the inner shell orbitals are called core electrons. Since the core electron shells correspond to noble gas electron configurations, we can abbreviate electron...
Electron Configurations
Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest energy available), Pauli exclusion principle (no two electrons can have the same set of four quantum numbers), and Hund’s rule of maximum multiplicity (whenever possible, electrons retain unpaired spins in degenerate orbitals).
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s,...
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s,...
What is Matter?
The substance of the universe—from a grain of sand to a star—is called matter. Scientists define matter as anything that occupies space and has mass. An object’s mass and its weight are related concepts, but not quite the same. An object’s mass is the amount of matter contained in the object and is the same whether that object is on Earth or in the zero-gravity environment of outer space. An object’s weight, on the other hand, is its mass as affected by the pull of gravity. Where gravity...
Atomic Structure
The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for "indivisible," from which the modern term "atom" is derived. In the 19th century, John Dalton proposed the atomic theory that is still largely correct today. He put forth five postulates to explain how atoms made up the world around us. (1) All matter is composed of infinitely small particles or atoms. (2) All atoms of a given element are identical to one another and (3) are...


