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La desorción estimulada por fotones es una fuente sustancial de sodio en la atmósfera lunar
1Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway 08854-8019, USA.
Nature
|August 24, 1999
Resumen
La desorción estimulada por fotones libera eficientemente átomos de sodio de las superficies lunares. Este proceso, impulsado por la luz ultravioleta, es una fuente importante para la tenue atmósfera de la Luna, con una desorción térmica también importante para Mercurio.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- Química de la atmósfera química de la atmósfera
- Física de la superficie Física de las superficies
Sus antecedentes:
- Mercurio y la Luna poseen tenues atmósferas que contienen sodio atómico y potasio.
- Estos elementos requieren un reabastecimiento continuo debido a los cortos tiempos de retención (horas).
- Los mecanismos de reabastecimiento propuestos incluyen pulverización, impactos, desorción térmica y desorción estimulada por fotones, con procesos dominantes poco claros.
Objetivo del estudio:
- Para investigar la desorción estimulada por fotones de sodio de superficies simuladas de silicato lunar.
- Determinar la eficiencia y los mecanismos de liberación del átomo de sodio inducida por fotones ultravioleta.
- Para evaluar la contribución de la desorción estimulada por fotones a las atmósferas de la Luna y Mercurio.
Principales métodos:
- Experimentos de laboratorio que simulan las condiciones de la superficie lunar.
- Bombardeo de las superficies de silicato con fotones ultravioleta (longitud de onda < 300 nm) a aproximadamente 250 K. Bombardeo de las superficies de silicato con fotones ultravioleta (longitud de onda < 300 nm) a aproximadamente 250 K. Bombardeo de las superficies de silicato con fotones ultravioleta (longitud de onda < 300 nm) a aproximadamente 250 K. Bombardeo de las superficies de silicato con fotones ultravioletas (longitud de onda < 300 nm) a aproximadamente 250 K.
- Análisis de la desorción del átomo de sodio inducida por excitaciones electrónicas.
Principales resultados:
- La desorción estimulada por fotones de sodio de superficies lunares simuladas es muy eficiente.
- La desorción es impulsada principalmente por excitaciones electrónicas, no por procesos térmicos o transferencia de momento.
- El flujo solar de fotones ultravioleta es suficiente para contribuir significativamente al sodio atmosférico de la Luna.
Conclusiones:
- La desorción estimulada por fotones es un proceso clave que suministra sodio a la atmósfera de la Luna.
- En Mercurio, tanto la desorción estimulada por fotones como la desorción térmica son probablemente importantes para el sodio atmosférico.
- Comprender estas interacciones superficie-atmósfera es crucial para la ciencia planetaria.
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