Resumo:
One way to know the physical properties of Trans-Neptunian objects (TNOs) is the analysis of stellar occultations by these objects. The prediction of a stellar occultation basically depends on comparisons of TNOs' ephemeris and stars positions. However, with the current knowledge of TNOs' ephemeris and star catalogs, it is not possible to do good predictions of the event without a process of refinement of stars positions and TNOs' orbits. With the release of GAIA catalog the limitations with respect to the stars will be overcome. This work consists of developing a methodology to refine the orbits of some TNOs. For this purpose, we use calibrated data from the Dark Energy Survey (DES) observed in 2013. The methodology basically consists in knowing the pointings, observation date and the size of fields observed with the Dark Energy Camera (DECam), to identify the known Solar System objects located in the fields. Then retrieve the images which contains some TNOs and with the positions obtained after doing astrometry, added to the existing ones from literature, we do a better fit of TNOs and Centaurs' orbits found by DECam. Finally, we predict stellar occultations by using an astrometric star catalog. We managed to complete this process for six TNOs delivering their occultation predictions.
