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Isótopos de bario en meteoritos condríticos: implicaciones para los modelos de depósitos planetarios
Michael C Ranen1, Stein B Jacobsen
1Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA. ranen@fas.harvard.edu
Science (New York, N.Y.)
|October 7, 2006
Resumen
El análisis de isótopos de bario revela diferencias entre las condritas y la Tierra, lo que sugiere una mezcla incompleta de material estelar en la nebulosa solar temprana. Esto indica que la nebulosa solar no estaba completamente homogeneizada durante la formación de los planetas.
Área de la Ciencia:
- Cosmoquímica es la cosmoquímica.
- Geoquímica de isótopos La geoquímica de isótopos es la química de los isótopos.
- Ciencias planetarias Ciencias planetarias.
Sus antecedentes:
- Comprender la composición inicial de la nebulosa solar es crucial para las teorías de formación planetaria.
- Las variaciones isotópicas en los materiales presolares pueden proporcionar información sobre la nucleosíntesis estelar y la mezcla de nebulosas.
Objetivo del estudio:
- Para investigar las variaciones de isótopos de bario entre las condritas y la Tierra.
- Para evaluar el grado de mezcla de materiales presolares en la nebulosa solar.
Principales métodos:
- Mediciones de alta precisión de las relaciones de isótopos de bario (137Ba/136Ba y 138Ba/136Ba).
- Análisis comparativo de datos isotópicos de meteoritos condríticos y muestras terrestres.
Principales resultados:
- Se observaron diferencias significativas, de hasta 25 ppm para 137Ba/136Ba y 60 ppm para 138Ba/136Ba, entre las condritas y la Tierra.
- Las condritas exhiben un ligero exceso de material derivado de supernovas en comparación con la Tierra.
Conclusiones:
- Las discrepancias isotópicas observadas apuntan a una mezcla incompleta de material nucleosintético dentro de la nebulosa solar.
- La nebulosa solar no estaba perfectamente homogeneizada antes o durante las primeras etapas de la formación planetaria.
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