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Cassini encuentra una atmósfera de oxígeno y dióxido de carbono en la luna helada de Saturno Rhea
B D Teolis1, G H Jones, P F Miles
1Southwest Research Institute, Space Science and Engineering Division, 6220 Culebra Road, San Antonio, TX 78238, USA. ben.teolis@swri.org
Science (New York, N.Y.)
|November 27, 2010
Resumen
Cassini detectó una fina atmósfera de oxígeno y dióxido de carbono en la luna de Saturno Rhea. Esta atmósfera probablemente se forma de la descomposición del hielo de agua debido al plasma magnetosférico de Saturno, lo que sugiere un depósito de oxígeno subterráneo.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- La astroquímica es astroquímica.
- Física del espacio Física del espacio
Sus antecedentes:
- La luna de Saturno Rhea, un cuerpo helado, fue investigada para la composición atmosférica.
- Anteriores observaciones remotas sugirieron la presencia de oxidantes superficiales en lunas heladas.
- Comprender la composición de la exosfera es clave para caracterizar los entornos lunares helados.
Objetivo del estudio:
- Para determinar la composición de la tenue atmósfera de Rea utilizando mediciones in situ.
- Para investigar la fuente y los mecanismos de sustento de la atmósfera de Rhea.
- Evaluar las implicaciones para otros cuerpos helados en el sistema solar.
Principales métodos:
- Mediciones de sobrevuelo de la nave espacial Cassini.
- Detección in situ de los gases atmosféricos (O2, CO2)).
- Análisis del flujo de salida de iones para comprender los procesos de pérdida atmosférica.
Principales resultados:
- Detección de una tenue atmósfera compuesta de oxígeno (O(2) y dióxido de carbono (CO(2) alrededor de Rea.
- La evidencia sugiere que la atmósfera es sostenida por la radiólisis del hielo de agua de superficie.
- Las observaciones indican que la ionización de recolección es un mecanismo significativo de pérdida atmosférica.
Conclusiones:
- Rhea posee una atmósfera oxidante, consistente con las reservas de oxígeno radiolítico en su hielo.
- La presencia de CO2 apunta a la radiólisis que involucra sustancias orgánicas superficiales o fuentes endógenas.
- Este hallazgo apoya la hipótesis de procesos similares que ocurren en otras lunas heladas como Europa y Ganímedes.
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