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Una sorprendente anomalía de isótopos de nitrógeno en los meteoritos Bencubbin y Weatherford

C A Prombo, R N Clayton

Science (New York, N.Y.)

|November 22, 1985

Resumen

Los meteoritos de hierro-piedra Bencubbin y Weatherford muestran niveles inusualmente altos de nitrógeno-15. Este exceso de nitrógeno puede provenir de la nucleosíntesis estelar o de procesos químicos extremos de baja temperatura en las primeras nubes del sistema solar.

Área de la Ciencia:

Cosmoquímica es la cosmoquímica.
La geoquímica de los isótopos es la geoquímica de los isótopos.
Ciencias planetarias Ciencias planetarias.

Sus antecedentes:

Las proporciones de isótopos de nitrógeno en los meteoritos proporcionan información sobre los primeros procesos del sistema solar.
Los meteoritos de hierro-piedra, como Bencubbin y Weatherford, son raros y conservan firmas químicas únicas.

Objetivo del estudio:

Para investigar el origen de la anormal proporción nitrógeno-15/nitrógeno-14 observada en los meteoritos Bencubbin y Weatherford.
Explorar posibles mecanismos de fraccionamiento químico nucleosintético o presolar responsables del enriquecimiento isotópico observado.

Principales métodos:

Análisis isotópico de nitrógeno en muestras masivas de meteoritos.
Comparación de las relaciones isotópicas observadas con modelos de nucleosíntesis y fraccionamiento químico.

Principales resultados:

Los meteoritos Bencubbin y Weatherford exhiben proporciones de nitrógeno-15/nitrógeno-14 hasta el doble de la abundancia normal.
El enriquecimiento observado es consistente con un origen nucleosintético presolar o fraccionamiento isotópico a temperatura extremadamente baja (por debajo de 40 K).

Conclusiones:

La composición anómala de isótopos de nitrógeno en estos meteoritos ofrece pistas sobre los procesos que ocurrieron antes o durante la formación del sistema solar.
Investigaciones adicionales pueden distinguir entre un origen de nucleosíntesis estelar y procesamiento químico presolar basado en isótopos de nitrógeno.

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