  Asteroid 4 Vesta has a set of parallel troughs aligned with its equator.
Although previous evaluations suggest that it is of shock fracturing tectonic
origin, we propose that the equatorial troughs can be created by secondary
cratering from the largest impact basin, Rheasilvia. We calculated the
trajectories of ejecta particles from Rheasilvia by considering Vesta's rapid
rotation. As a result, we found that secondary craters should be parallel to
the latitude. In particular, if we assume that ejecta particles are launched at
an initial launch velocity of approximately 350-380 m/s and a launch angle of
25 degree, the parallel equatorial troughs, the Divalia Fossae, can be suitably
explained by secondary cratering. This model works well on objects, such as
Haumea, Salacia, and Chariklo, but not on Mercury, the Moon, and regular
satellites.
