The azimuthal distribution of ejecta mass from oblique impacts into sand

Abstract

We measure ejecta mass as a function of azimuthal and impact angle for 104 m/s oblique impacts into sand. We find that the ejecta mass distribution is strongly sensitive to azimuthal angle with as high as 8 times more mass in ejecta on the downrange side compared to the uprange side. Crater radii, measured from the impact point, are measured at different impact and azimuthal angles. Crater ejecta scaling laws are modified to depend on azimuthal and impact angle. We find that crater radii are sensitive to both impact and azimuthal angle but the ejecta mass as a function of both angles can be estimated from the cube of the crater radius without an additional angular dependent function. The ejecta distributions are relevant for processes that depend upon the integrated properties of approximately 100 m/s impacts occurring in the outer solar system and possibly during planetesimal formation.