Técnicas de detección y caracterización de la materia interplanetaria próxima a la Tierra desde observatorios en tierra

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Astrofísica y Ciencias de la Atmósfera, leída el 05/06/2017Interplanetary matter covers a wide range of mass and size in the Universe, from micrometric dust to multi-kilometre asteroids. This matter plays countless roles in planetary sciences. Dust fills the space in the Solar System, but also in a myriad of exoplanetary systems. Indeed, the interplanetary dust usually outshines the planets in infrared and these hot debris disks have already been observed in several exoplanetary systems. The near-Earth interplanetary matter is also relevant for Earth sciences and space exploration. Extraterrestrial dust plays several roles in the upper atmosphere. Moreover the asteroids are a threat for humankind due to the energy they release in the case of impact against the planet. Asteroids larger than 1 km could produce global devastation and 90% of them are already catalogued. Current efforts are focused on the population larger than 140 m, able to produce an impact of regional proportions. Beyond Earth’s atmosphere, these bodies pose a hazard to spacecraft, especially the small particles that are the most numerous but still carry enough energy to jeopardise their systems. This dissertation undertakes the research of the interplanetary matter near the Earth using two different observational approaches. The first one is based on the detection of the sunlight reflected by the bodies. Individuals bodies can be observed with the use of telescopes, they are the asteroids. For objects close to the Earth the accessible range in size is wider, down to the decametre size and consequently this population are a probe to general population of asteroids in the Solar System. Especially if we consider that recent works suggest that objects larger and smaller than 200 m could be two different populations, being the smaller monolithic bodies while larger ones are more likely rubble piles. And we only have access to the smaller population if they come close enough to the be observable. The detection and characterisation of these nearby population require networks of medium-sized telescopes to survey and track them. We design a robotic system (the TBT telescopes) for the European Space Agency as a prototype for a future network. The first unit is already installed in Spain and we present the results of the commissioning. Additionally we evaluate the expected performance of such an instrument using a simulation with a synthetic population. We consider that the system designed is a powerful instrument for nearby asteroid discovery and tracking. It is based on commercial components, and therefore ready for a scalable implementation in a global network...Bajo el término de materia interplanetaria se engloban objetos en un gran rango de masas y tamaños en el Universo, desde el polvo micrométrico hasta los asteroides de centenares de kilómetros de diámetro. Esta materia toma parte de innumerables procesos en las ciencias planetarias. Además el polvo no sólo está presente en el espacio del Sistema Solar, sino también en una infinidad de sistemas extrasolares. Más aún, el polvo interplanetario es más brillante en el infrarrojo que los propios planetas y ya se han observado muchos de estos discos circunestelares de polvo caliente. La materia interplanetaria en las cercanías de nuestro planeta es también relevante para el estudio de las ciencias de la Tierra y en la exploración espacial. El polvo extraterrestre participa en muchos procesos que tienen lugar en las capas más altas de la atmósfera. Asimismo los asteroides son una amenaza para la humanidad debido a la energía que pueden liberar en caso de impacto contra la Tierra. Se considera que los asteroides mayores de 1 km podrían provocar una catástrofe de proporciones globales y por ello el 90% de ellos ya han sido identificados. Actualmente los esfuerzos se centran en los objetos mayores de 140 m, con consecuencias sólo a nivel regional en caso de colisión. Fuera de la atmósfera terrestre estos cuerpos suponen un peligro para las naves espaciales, especialmente las partículas pequeñas que son las más numerosas y que pese a ello transportan energía suficiente como para comprometer su funcionamiento. Esta tesis estudia la materia interplanetaria desde dos aproximaciones observacionales distintas. Por un lado se observa la luz solar reflejada por estos cuerpos. En este caso encontramos a los asteroides, cuerpos que se pueden observar con telescopios hasta cierto tamaño. Para la población de objetos próximos a la Tierra el rango de tamaños que podemos observar es mayor, hasta tamaños de apenas decenas de metros. Por ello esta población se considera como una muestra relevante a la hora de estudiar la población general de asteroides en el Sistema Solar. Especialmente cuando estudios recientes afirman que puede haber una diferencia estructural entre las poblaciones con diámetro mayor y menor a unos 200 m, donde los pequeños son objetos monolíticos mientras que los grandes son agregados de objetos. Los objetos menores sólo son accesibles a los instrumentos si se aproximan lo suficiente a la Tierra. La detección y caracterización de estos objetos próximos requieren redes de telescopios de tamaño moderado. En este trabajo presentamos el diseño de un sistema robótico (los telescopios TBT) para la Agencia Espacial Europea (ESA), como prototipos de una red futura. El primero de ellos se encuentra ya instalado en España y se incluyen los resultados del comisionado. Por otro lado hemos analizado el rendimiento que se espera de ellos con ayuda de una simulación de las observaciones de una población sintética de objetos. Consideramos que el sistema diseñado es una herramienta potente para el descubrimiento y seguimiento de estos objetos próximos a la Tierra. Es un sistema basado en componentes comerciales y que por tanto se puede replicar para desarrollar una red global...Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEunpu

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