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Evidencia de hielo de agua cerca del polo norte de Mercurio de las mediciones del espectrómetro de neutrones
David J Lawrence1, William C Feldman, John O Goldsten
1The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. david.j.lawrence@jhuapl.edu
Science (New York, N.Y.)
|December 1, 2012
Resumen
Se confirma el hielo de agua en los polos de Mercurio, detectado por la nave espacial MESSENGER. Los datos de neutrones y radares revelan una capa gruesa y rica en hidrógeno, probablemente hielo de agua pura, debajo de una capa superficial más delgada.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- Astrogeología y Astrogeología.
- La geoquímica espacial es la geoquímica espacial.
Sus antecedentes:
- La región polar norte de Mercurio exhibe depósitos de radar brillante, lo que sugiere la presencia de materiales volátiles.
- Se supone que las regiones permanentemente sombreadas en los polos de Mercurio albergan hielo de agua debido a las variaciones extremas de temperatura.
Objetivo del estudio:
- Para investigar la composición y estructura de los depósitos polares de Mercurio utilizando datos de espectrometría de neutrones.
- Para determinar la presencia y abundancia de hidrógeno, indicativo de hielo de agua, en las regiones polares de Mercurio.
Principales métodos:
- Análisis de las mediciones del flujo de neutrones epitermal y rápido del espectrómetro de neutrones de la nave espacial MESSENGER.
- Integración de los datos de neutrones con las observaciones de radar existentes de los depósitos polares de Mercurio.
Principales resultados:
- La disminución del flujo de neutrones de la región polar norte de Mercurio es consistente con la presencia de hielo de agua.
- Los datos de neutrones indican una capa rica en hidrógeno (>10 cm de espesor) debajo de una capa superficial (10-30 cm de espesor) con un menor contenido de hidrógeno.
- Los datos combinados se ajustan mejor a un modelo donde la capa enterrada es casi hielo de agua puro, con la capa superior que contiene <25% de hidrógeno equivalente a agua.
Conclusiones:
- Los hallazgos apoyan fuertemente la presencia de depósitos significativos de hielo de agua en las regiones polares permanentemente sombreadas de Mercurio.
- La masa de agua inferida (2 × 10 ^ 16 a 10 ^ 18 gramos) es consistente con el envío de volátiles por cometas o asteroides.
- Esta investigación proporciona información crucial sobre la historia y la distribución del agua en el sistema solar interior.
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