Determinação do período de rotação de objetos em órbita próxima da Terra como parte do projeto IMPACTON

Abstract

The NEOs (Near-Earth Objects) are small bodies of the Solar System in orbits close to the Earth's orbit, these objects are divided into 4 subgroups: Atiras, Aten, Apollo, and Amor. Studying the physical properties of these bodies is important not only for a better understanding of their origin and evolution but also allows the definition of strategies in case of discovering an object that presents a risk of impacting the Earth's surface. Currently, 29440 objects classified as NEOs are known, but for only 6.5% of them the rotation period has been determined. As part of IMPACTON, the present work aims to determine the rotation period of NEOs from the analysis of their light curves. The adopted methodology is the photometric observation of NEOs without a known rotation period, using the Observatório Astronômico do Sertão de Itaparica (OASI) of the IMPACTON project. The data allows to obtain the light curve of the objects, that is, how their brightness changes over time. Assuming that this brightness variation is mainly due to the non-spherical shape of the objects, from the light curve analysis it is possible to derive the rotation period. The data reduction has been performed using both the software MPO Canopus and the Pipeline IMPACTON, developed by J.M. Carvano. This last automatically identifies and determines the instrumental magnitudes of all the objects in an image but, although much efficient, is still in a testing phase. In this work we obtained data for 14 NEOs and for 12 of these we determined their rotation periods, with values ranging between 1.9 hours and 10.4 hours. For one asteroid we estimated just a lower limit for the period, while for another one we did not obtained conclusive results.