Determinacao das Propriedades Rotacionais de Asteroides em Orbitas Proximas da Terra Atraves do Projeto IMPACTON

Abstract

Photometric data for 35 Near-Earth Asteroids (NEA) were obtained in the present work. The data were acquired at the 1-m telescope of the Observatório Astronômico do Sertão de Itaparica - OASI - (Itacuruba, PE) and were used to derive the rotational period and an estimate of the shape and the spin direction of the observed asteroids. These physical properties are fundamental in order to achieve a better knowledge on the formation and evolution not only of the observed bodies but also of the NEA population as a whole. Moreover, these properties are of upmost relevance in the case of objects which might collide with Earth in the future. Presently, only 7% of the nearly 14,500 known NEA do have their rotational period determined and for just 1% of these also the spin direction is known. It is thus clear the need for an increase of the sample of objects with known rotational properties in order to perform robust statistical analyses. In the present study the rotational period was determined using a Fourier series analysis method, while the spin direction and shape were derived using a lightcurve inversion method. The rotational period, varying from 5 minutes up to 11 hours, for 26 asteroids was here derived while an indication was obtained for other 7 objects. For 2 asteroids among those with determined rotational period, we also derived the spin direction and a shape model.