Meteoroid impacts onto asteroids: a competitor for Yarkovsky and YORP

TL;DR

This paper investigates how meteoroid impacts can influence asteroid orbits and spins, potentially rivaling the effects of Yarkovsky and YORP, especially when ejecta momentum transfer is considered, highlighting a previously underestimated factor in asteroid dynamics.

Contribution

It demonstrates that meteoroid impacts, enhanced by ejecta momentum transfer, can significantly affect small asteroid dynamics, rivaling established effects like Yarkovsky and YORP.

Findings

Meteoroid impacts can have effects comparable to Yarkovsky and YORP under certain conditions.

Ejecta momentum transfer may amplify impact effects by two orders of magnitude.

Further research is needed to confirm the extrapolation of laboratory results to real asteroid collisions.

Abstract

<Abridged> The impact of a meteoroid onto an asteroid transfers linear and angular momentum to the larger body, which may affect its orbit and its rotational state. Here we show that the meteoroid environment of our Solar System can have an effect on small asteroids that is comparable to the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects under certain conditions. The momentum content of the meteoroids themselves is expected to generate an effect much smaller than that of the Yarkovsky effect. However, momentum transport by ejecta may increase the net effective force by two orders of magnitude for impacts into bare rock surfaces. This result is sensitive to the extrapolation of laboratory microcratering experiment results to real meteoroid-asteroid collisions and needs further study. If this extrapolation holds, then meteoroid impacts are more important to the dynamics of small asteroids than had previously been considered.