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La ablación, el flujo y las implicaciones atmosféricas de los meteoros inferidas de los aerosoles estratosféricos
D J Cziczo1, D S Thomson, D M Murphy
1Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA.
Science (New York, N.Y.)
|March 7, 2001
Resumen
Las partículas de aerosol estratosférico contienen hierro meteórico significativo, lo que indica una afluencia extraterrestre de 8-38 gigagramos anuales. La composición sugiere que el material extraterrestre en la estratosfera no es cóndrico.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Ciencias de la atmósfera Ciencias atmosféricas.
- El polvo cósmico.
Sus antecedentes:
- Las partículas de aerosoles estratosféricos juegan un papel crucial en la química atmosférica y el clima.
- Comprender el componente extraterrestre de estas partículas es clave para descifrar los procesos atmosféricos de la Tierra.
Objetivo del estudio:
- Para analizar la composición de las partículas de aerosol estratosférico.
- Para cuantificar la afluencia extraterrestre a la Tierra.
- Determinar el origen y la composición del material extraterrestre en la estratosfera.
Principales métodos:
- Análisis de una sola partícula de muestras de aerosol estratosférico.
- Espectrometría de masas para determinar la composición de los elementos (Fe, Na, Mg, Ca).
- Comparación de las proporciones elementales de partículas con las composiciones de meteoritos condríticos.
Principales resultados:
- Aproximadamente el 50% de las partículas analizadas contienen 0.5-1.0% de hierro meteorítico en masa.
- Se estima que la afluencia anual de extraterrestres oscila entre 8 y 38 gigagramos.
- Las partículas estratosféricas exhiben proporciones más altas de Na/Fe y más bajas de Mg/Fe, Ca/Fe en comparación con las condritas.
Conclusiones:
- El material extraterrestre en la estratosfera no es de origen condrítico.
- La fracción de ablación del material extraterrestre entrante es probable que esté en el extremo inferior de las estimaciones anteriores.
- Estos hallazgos refinan nuestra comprensión de la contribución del polvo cósmico a la atmósfera de la Tierra.
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