ASTROMETRIA E REFINAMENTO DE ORBITAS DE TRANSNETUNIANOS E CENTAUROS: CAMINHANDO PARA PROCEDIMENTOS AUTOMATICOS DE REDUCAO E ANALISE DE DADOS

Abstract

Light curves from the occultation of a star by a distant body in the solar system allow us to meausre the dimensions of this latter with kilometric accuracies. This is rivaled only by measurements made by space probes. It also allows the detection and eventual study of very tenuous atmospheres (nanobar level) and that the neighbourhoods of the object be investigated in details (leading, for instance, to the discovery of a ring system around them). However, the obtention of such curves presumes the knowledge of their occurrence, that is, where and when on the Earth the occultation event can be observed. This involves a considerable amount of work towards the determination of the positions of the occulting bodies as well as the improvement of their orbits. It also involves the e↵ort for an accurate determination of the position of the star to be occulted. Thanks to the imminent publication of the first results from the GAIA space mission, such an e↵ort will soon be thoroughly unnecessary. In addition, with respect to the improvement of the orbits of solar system objects, great contribution is expected from the large surveys, the Large Synoptic Survey Telescope (LSST) in particular. In fact, along with the large number of observations, there is also the depth in magnitude. This means that not only will be possible to obtain a huge amount of accurate positions with the help of the results from GAIA but also to highly increase the number of studied objects. In this work, we deal with CCD observations of about 40 solar system objects among transneptunians and Centaurs, aiming at the determination of their positions and at the improvement of their orbits within a short (1-3 years) period after the date of the last observation. The main objective rests upon the prediction of stellar occultations by these objects as well as the respective organization of observational campaigns. The observations used here are part of the image data archive of our team and comprises data from the 1.6 m and 0.6m (IAG) telescopes at the Pico dos Dias Observatory (OPD) and the 2.4 m telescope at the Thai National Observatory (Thailand). The organization of this data archive, along with a preliminar pipeline to perform astrometry and orbit determination with the least possible user intervention, are also aimed. The point in this is to prepare us to a big data environment with which we will certainly deal in the near future. In this context, the work developed here should be used within our participation in the Dark Energy Survey (DES).