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Episodios de eyección de partículas desde la superficie del asteroide activo (101955) Bennu
D S Lauretta1, C W Hergenrother1, S R Chesley2
1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. lauretta@orex.lpl.arizona.edu chergen@lpl.arizona.edu.
Science (New York, N.Y.)
|December 7, 2019
Resumen
Los asteroides activos muestran pérdida de masa. Las eyecciones de partículas del asteroide Bennu, observadas por la nave espacial OSIRIS-REx, confirman que es un asteroide activo, revelando información sobre los mecanismos de eyección.
Área de la Ciencia:
- Investigación de objetos cercanos a la Tierra
- Ciencia de los asteroides y los cometas
- Geología planetaria
Sus antecedentes:
- Los asteroides activos son cuerpos celestes que exhiben una pérdida de masa en curso.
- El asteroide (101955) Bennu es un objetivo potencial de retorno de muestras de interés científico significativo.
- Comprender los mecanismos de pérdida de masa es crucial para la evolución de los asteroides y la evaluación de los peligros.
Objetivo del estudio:
- Para presentar pruebas de eyección de partículas del asteroide (101955) Bennu.
- Caracterizar los eventos de eyección observados y las partículas asociadas.
- Para investigar los posibles mecanismos que impulsan estos fenómenos de asteroides activos.
Principales métodos:
- Utilizó imágenes de la nave espacial OSIRIS-REx para detectar y analizar eventos de eyección de partículas.
- Velocidades estimadas de partículas, tamaños y energías para eventos importantes.
- Determinación de las trayectorias y propiedades fotométricas de los eyectos ligados gravitacionalmente.
- Evaluó múltiples hipótesis físicas para los eventos de eyección.
Principales resultados:
- Confirmado (101955) Bennu como un asteroide activo a través de repetidos eventos de eyección de partículas.
- Parámetros clave cuantificados de los mayores eventos de eyección, incluidas las regiones de origen y las energías.
- Se han observado partículas que orbitan temporalmente unidas por la gravedad de Bennu.
- Identificó varios mecanismos plausibles para la eyección de partículas.
Conclusiones:
- La actividad de Bennu proporciona un estudio de caso único para los fenómenos de asteroides activos.
- Las eyecciones observadas ofrecen información sobre los procesos superficiales en cuerpos pequeños.
- Se necesitan más investigaciones para determinar definitivamente los mecanismos de eyección dominantes.
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