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Formación de mega-impacto de la dicotomía hemisférica de Marte
Margarita M Marinova1, Oded Aharonson, Erik Asphaug
1California Institute of Technology, Division of Geological and Planetary Sciences, MC 150-21, Pasadena, California 91125, USA. mmm@caltech.edu
Nature
|June 27, 2008
Resumen
Un solo mega-impacto puede explicar la dicotomía hemisférica de Marte. Las simulaciones muestran que las condiciones de impacto específicas, incluidos el ángulo y la energía, pueden crear las diferencias de la corteza observadas entre las tierras altas del sur y las tierras bajas del norte.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- La geofísica es la geofísica.
- El cráter de impacto es el cráter de impacto.
Sus antecedentes:
- La dicotomía hemisférica de Marte, un marcado contraste en la elevación y el grosor de la corteza entre los hemisferios, sigue siendo poco comprendida.
- Los modelos de formación existentes, como la convección endogénica o los impactos múltiples, tienen limitaciones o improbabilidades estadísticas.
Objetivo del estudio:
- Para investigar la hipótesis de un solo mega-impacto para el origen de la dicotomía hemisférica de Marte.
- Para modelar las condiciones de impacto que podrían producir características consistentes con la dicotomía observada.
Principales métodos:
- Utilizó simulaciones hidrodinámicas tridimensionales para modelar un solo evento de impacto grande.
- Energía de impacto, velocidad y ángulo variados para evaluar su influencia en los estados posteriores al impacto.
Principales resultados:
- Las simulaciones indican que los impactos oblicuos (30-60 grados) con energías de (3-6) x 10(29) J y bajas velocidades (6-10 km/s) pueden generar un límite de eliminación de la corteza que coincide con el tamaño y la elipticidad de las tierras bajas del norte.
- La distribución de la fusión bajo estas condiciones es en gran medida localizada, preservando la evidencia del impacto.
Conclusiones:
- Un solo evento de mega impacto es una explicación viable para la dicotomía hemisférica de Marte.
- El momento y el ángulo de impacto son consistentes con las condiciones tempranas del sistema solar y las poblaciones de impactadores.
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