Physical and dynamical properties of selected Earth co-orbital asteroids

Abstract

We present our investigations of the physical and dynamical properties of selected Earth co-orbital asteroids. The photometric optical light curves as well as rotation periods and pole solutions for a sample of four Earth co-orbital asteroids, namely (138175) 2000 EE104 (P ​= ​13.9476 ​± ​0.0051 ​h), (418849) 2008 WM64 (P ​= ​2.4077 ​± ​0.0001 ​h), 2016 CA138 (P ​= ​5.3137 ​± ​0.0016 ​h) and 2017 SL16 (P ​= ​0.3188 ​± ​0.0053 ​h), are determined or improved and presented in this work. For this investigation, we combine observations carried out at the Bulgarian National Astronomical Observatory - Rozhen using the FoReRo2 instrument attached to the 2mRCC telescope as well as sparse data from AstDys2 database. Parallel to the rotational properties we did numerical dynamical simulations to investigate the orbital stability of those objects and to find out if there is a relation with their rotational properties. Our results show that the orbit stability is affected by the orbit itself and mainly its eccentricity and inclination, which are responsible for the close encounters with other Solar system planets. We cannot make a definitive conclusion about the relation between orbit stability and the rotational state of the asteroids, so we need further investigations and observations in order to prove or disprove it.