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Restricciones sobre la edad de formación del material cometario de la misión Stardust de la NASA
J E P Matzel1, H A Ishii, D Joswiak
1Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. matzel2@llnl.gov
Science (New York, N.Y.)
|February 27, 2010
Resumen
Las inclusiones cometarias como Coki se formaron más de 1,7 millones de años después de los primeros sólidos del sistema solar. Esto sugiere que el material formado en el sistema solar interior se incorporó más tarde en los cometas.
Área de la Ciencia:
- Cosmoquímica es la cosmoquímica.
- Ciencias planetarias Ciencias planetarias.
- La geoquímica de los isótopos es la geoquímica de los isótopos.
Sus antecedentes:
- Los cometas son restos del sistema solar primitivo, ofreciendo información sobre su formación.
- Comprender el momento de la formación de la inclusión cometaria es clave para los modelos de evolución del sistema solar.
Objetivo del estudio:
- Para determinar la escala de tiempo de formación de las inclusiones cometarias mediante el análisis de su composición isotópica.
- Para comparar los tiempos de formación de materiales cometarios con sus contrapartes meteoríticas, como las inclusiones ricas en calcio y aluminio (CAIs).
Principales métodos:
- Medición de la sistemática del isótopo 26Al-26Mg en una partícula refractaria (Coki) del cometa 81P/Wild 2.
- Utilizando la espectrometría de masas para analizar las abundancias isotópicas y restringir la presencia de 26Al.
Principales resultados:
- No se encontró evidencia de 26Mg radiogénico en la partícula de Coki.
- Se estableció un límite superior para la abundancia de 26Al en el momento de la formación de partículas: 26Al/27Al < 1 x 10(-5).
- La ausencia de 26Al indica que Coki se formó más de 1,7 millones de años después de la formación de CAI.
Conclusiones:
- Coki se formó significativamente más tarde que los primeros sólidos del sistema solar (CAIs).
- Esto implica que el material de alta temperatura del sistema solar interior fue procesado y transportado al sistema solar exterior.
- Las inclusiones cometarias representan material incorporado a los cometas millones de años después de las etapas iniciales de la formación del sistema solar.
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