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Tasa de acreción de las esferulas cósmicas medida en el Polo Sur
S Taylor1, J H Lever, R P Harvey
1US Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire 03755, USA.
Nature
|May 15, 1998
Resumen
Los investigadores recogieron micrometeoritos extraterrestres del hielo antártico para medir con precisión su afluencia. Los hallazgos revelan que aproximadamente el 90% de la masa de polvo cósmico submilimétrico entrante se pierde durante la entrada en la atmósfera.
Área de la Ciencia:
- Estudios del polvo cósmico Estudios del polvo cósmico
- Ciencias planetarias Ciencias planetarias.
- La geofísica es la geofísica.
Sus antecedentes:
- Los micrometeoritos, partículas extraterrestres <1mm, representan la mayor parte de la masa acumulada por la Tierra.
- Ofrecen información sobre asteroides, cometas, planetas y granos presolares.
- Las mediciones de flujo anteriores sufrieron incertidumbres debido a la intemperie, ineficiencias de recolección y mala datación.
Objetivo del estudio:
- Para superar las limitaciones en las mediciones anteriores de flujo de micrometeoritos.
- Para determinar con precisión el flujo y la distribución de masa de las esferulas cósmicas.
- Para restringir los modelos de supervivencia de la entrada atmosférica de micrometeoritos.
Principales métodos:
- Colección de miles de micrometeoritos bien conservados y fechados del pozo de agua del Polo Sur.
- Análisis de esferulas cósmicas de 50-700 micras (micrometeoritos fundidos).
- Estimación de la abundancia de micrometeoritos no fundidos para dar cuenta de la masa entrante total.
Principales resultados:
- Estimaciones precisas de la distribución del flujo y la masa de las esferulas cósmicas.
- Indicación de que aproximadamente el 90% de la masa de partículas submilimétricas entrantes se evapora durante la entrada en la atmósfera.
- Identificación de la pérdida de esferas de piedra pequeñas y ricas en vidrio de los depósitos de aguas profundas.
Conclusiones:
- El pozo de agua del Polo Sur proporciona una fuente única y confiable para la investigación de micrometeoritos.
- La entrada en la atmósfera reduce significativamente la masa de los micrometeoritos entrantes.
- Los datos proporcionan restricciones cruciales para comprender las probabilidades de supervivencia de micrometeoroides.
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