V-type NEAs: Impacts and close encounters with terrestrial planets

Abstract:

V-type Near-Earth Asteroids (V-NEAs) are basaltic asteroids with a perihelion less than 1.3 AU. Their
most likely origin is the Vesta family in the main asteroid belt, even though V-type asteroids can be
found in other families (i.e. Eunomia, Magnya, etc...), albeit in significantly smaller numbers. We are
mainly interested in the statistics of close encounters and impacts between V-NEAs and the
terrestrial planets, within 10 Myr. For impacts, we primarily aim to establish the energy release and size
of craters on planetary surfaces, especially for the Earth. We performed numerical computations of
orbit and simulated crater formation.
First results show that V-NEAs (see Fig. 1 for their size distribution in the initial osculating elements in the

semi-major axis - inclination plane) have close encounters with all the terrestrial planets (with a distance

less than 0.005 au from the planet) and they mainly collide with Venus and the Earth. Indeed, our preliminary

results of 120 integrated orbits reveal that ~1/10 of them are on impact trajectories during the grand-total

integrational time. Some impacts on the Earth have the potential to produce craters as large as 30 km in

diameter, with possibly catastrophic outcomes.