Three-dimensional Particle-in-cell Simulations of the Solar Wind Interaction with Asteroid 2016 HO3

Abstract

The recently discovered asteroid 2016 HO3 is the most stable quasi-satellite of our Earth. Several missions to 2016 HO3 have been proposed, including the Tianwen-2 mission of China. Here we study the solar wind interaction with 2016 HO3 with three-dimensional particle-in-cell simulations. It is found that the sunlit surface can be positively charged to more than +10 V, and the shadowed surface is negatively charged to lower than −30 V. The typical electric field on the sunlit surface is about 2 V m−1 but can increase up to 20 V m−1 near the terminator. There is a plasma wake behind 2016 HO3 with a reduced plasma density. Normally, the ion density can be reduced to about 0.3 of the solar wind density at 100 m downstream from 2016 HO3, and the plasma wake is confined by a Mach cone with a cone angle of about 6.°5. In addition, we find that both the solar wind parameters and the secondary electron emission can affect the surface charging, which, in return, changes the wake structure.