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Composición neutral de la atmósfera superior de Venus: resultados preliminares del pionero Venus Orbiter
Science (New York, N.Y.)
|February 23, 1979
Resumen
Las mediciones del orbitador Pioneer Venus revelan que el oxígeno atómico es el principal constituyente termosférico por encima de 155 km, con temperaturas que varían significativamente en función del ángulo solar. Las relaciones isotópicas se alinean con los valores de la Tierra.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- Ciencias de la atmósfera Ciencias atmosféricas.
- Física del espacio Física del espacio
Sus antecedentes:
- La termosfera de Venus es una región clave para comprender la dinámica atmosférica y la química.
- El conocimiento previo de la composición de la atmósfera superior de Venus y los perfiles de temperatura era limitado.
Objetivo del estudio:
- Para llevar a cabo mediciones in situ de la composición neutral y la temperatura de la termosfera de Venus.
- Para determinar la abundancia relativa de los principales gases y su variación con la altitud y la iluminación solar.
Principales métodos:
- Utilizó un espectrómetro de masas cuádrupolo a bordo del orbitador Pioneer Venus.
- Realizó mediciones in situ de partículas neutras y derivó la temperatura de las alturas de la escala.
Principales resultados:
- Se confirmó la presencia de los principales constituyentes: dióxido de carbono (CO2), monóxido de carbono (CO), nitrógeno (N2), oxígeno atómico (O) y helio (He).
- CO2 identificado como el gas más abundante por debajo de 155 km en la región del terminador.
- Se encontró que el oxígeno atómico era el constituyente dominante por encima de 155 km, con relaciones O/CO2 más altas de lo esperado.
- Temperaturas termosféricas observadas que van desde aproximadamente 400 K en un ángulo del cenit solar de 69 grados hasta 230 K a 90 grados.
- Determinó que las relaciones isotópicas de oxígeno y carbono son comparables a los valores terrestres.
Conclusiones:
- El oxígeno atómico juega un papel más significativo en la termosfera superior de Venus de lo que se suponía anteriormente.
- La temperatura termosférica exhibe una fuerte dependencia del ángulo del cenit solar, lo que indica procesos dinámicos.
- La composición isotópica sugiere orígenes comunes o procesos evolutivos similares para Venus y la Tierra.
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