Techniques for near-Earth interplanetary matter detection and characterisation from optical ground-based observatories

摘要

PhD Thesis defended the 5th June 2017. Universidad Complutense de Madrid. 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. 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. Meanwhile the bodies smaller than asteroids are observed using the atmosphere as a detector. When these particles collide with the atmospheric molecules they are heated, ablated, sublimated, and finally light is emitted by these hot vapours, what we call meteors. We conduct the investigation of these meteors to study the meteoroids. In particular we address two different topics: On one hand we explore the size/mass frequency distribution of meteoroids using flux determination when the collide into the atmosphere. We develop a method to determine this flux using video observations of meteors and analyse the properties of meteors as an optical proxy to meteoroids in order to maximise the detection. It yields three ground-based observational solutions that we transform into instrumental designs. First we design and develop a meteor all-sky detection station for Observatorio UCM and use the Draconids 2011 campaign as a showcase for the flux determination, with successful results. Then we investigate the observation of meteors with instruments in stratospheric balloons, overcoming troposphere handicaps like weather or extinction. On the other hand we design a filter set for narrow-band photometry for meteoroid characterisation, equivalent to low-R spectroscopy. We reproduce the classification of meteors using synthetic photometry over a spectra catalogue. We find the V-R colour to have a significant dependence to meteor speed and meteoroid composition, what implies a significant detection bias for unfiltered or broadband instruments.