Oxygen Isotopic Composition of an Enstatite Ribbon of Probable Cometary Origin
| Autor: | Gary R. Huss, D. Joswiak, J. B. Lewis, Ryan C. Ogliore, Alexander N. Krot, Kazuhide Nagashima, Kainen L. Ut, Donald E. Brownlee |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Solar System
FOS: Physical sciences Astrophysics engineering.material 010502 geochemistry & geophysics 01 natural sciences Article Crystal Interplanetary dust cloud 0103 physical sciences Ribbon Cluster (physics) Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Earth and Planetary Astrophysics (astro-ph.EP) Physics Solar wind Geophysics Meteorite Space and Planetary Science Physics::Space Physics Enstatite engineering Astrophysics::Earth and Planetary Astrophysics Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | Meteorit Planet Sci |
| Popis: | Filamentary enstatite crystals are found in interplanetary dust particles of likely cometary origin but are very rare or absent in meteorites. Crystallographic characteristics of filamentary enstatites indicate that they condensed directly from vapor. We measured the O isotopic composition of an enstatite ribbon from a giant cluster interplanetary dust particle to be $\delta^{18}\rm{O}{=25{\pm}55}$, $\delta^{17}\rm{O}{=-19{\pm}129}$, $\Delta^{17}\rm{O}{=-32{\pm}134}$ (2$\sigma$ errors), which is inconsistent at the 2$\sigma$ level with the composition of the Sun inferred from the Genesis solar wind measurements. The particle's O isotopic composition, consistent with the terrestrial composition, implies that it condensed from a gas of non-solar O isotopic composition, possibly as a result of vaporization of disk region enriched in $^{16}$O-depleted solids. The relative scarcity of filamentary enstatite in asteroids compared to comets implies either that this crystal condensed from dust vaporized \textit{in-situ} in the outer Solar System where comets formed, or it condensed in the inner Solar System and was subsequently transported outward to the comet-forming region. |
| Databáze: | OpenAIRE |
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