Bennu’s Natural Sample Delivery Mechanism: Estimating the Flux of
Bennuid Meteors at Earth
Abstract
NASA’s OSIRIS-REx mission observed millimeter- to centimeter-scale
pebbles being ejected from the surface of asteroid (101955) Bennu,
indicating that Bennu is an active asteroid. About 30% of these
particles escape from Bennu, and the minimum orbital intersection
distance (MOID) between Bennu and Earth suggest the possibility of a
‘Bennuid’ particle flux at Earth. We characterize the evolution of
Bennu’s particle stream and potential for meteor flux by simulating
weekly particle ejections between the years 1780 - 2135 continuing their
dynamical evolution until 2200. Ejections are modelled as a discrete
release of 95 particles every week. The meteoroid stream is found to
circularize in 80 +/- 40 years. Individual particles and streams remain
associable to Bennu for the entire 420 years simulated. Particle flux at
Earth is predicted to begin in 2101, as the Bennu-Earth MOID reaches
minimum values. The year of highest particle flux, 2182, experiences 161
Earth intersections and accounts for ~1/4 of our
predicted meteors. Our methods can be expanded to study the history and
structure of the general meteoroid population and to estimate flux from
specific near-Earth asteroids.