Physical properties of NEOs derived from their phase curves

Abstract

ABSTRACT The observation of Near Earth objects (NEOs) allows us to study the physical properties of the smallest size bodies of our Solar System and help impose constraints on their origin and evolution. The solar phase curve is a very important tool to derive diverse physical properties of a small body so that we set up an observational campaign to derive the phase curve parameters (H, G1, G2) for a large number of NEOs. We present here the obtained phase curves for 12 NEOs, along with the rotation period for two of them and the V–R colour for four. The data was acquired mainly at the Astronomical Observatory of Sertão de Itaparica (Brazil), with some NEOs also observed at the Osservatorio di Campo Imperatore (Italy). Considering all the objects observed throughout our campaign we analysed a homogeneous dataset of 30 NEOs along with data acquired by ATLAS (Asteroid Terrestrial-impact Last Alert System telescopes survey) for MB asteroids. The behavior in the phase space G1-G2 of 21,865 MBA and 103 NEOs was analysed, separating the objects in intervals of albedos and sizes. From the large MB data set we found evidence that the distribution in the G1-G2 phase space has strong dependence not only on the albedo but also on the object’s size. This is particularly true for the smaller objects. The main result being that, on the contrary to what occurs with the MB larger objects, we are unable to estimate the albedo of a NEO from its phase curve parameters.