Estimating Annual Meteor Flux from Active Asteroid Bennu

NASA’s OSIRIS-REx mission launched in September of 2016 to survey and sample the surface of the near-earth asteroid (101955) Bennu. During observations of Bennu, mission scientists observed millimeter- to centimeter-scale pebbles ejecting off the surface of the asteroid, leading to Bennu’s designation as an ‘active asteroid’ [1]. Many of these particles have been observed to follow hyperbolic trajectories, and the orbital intersection between Bennu and Earth suggests the possibility of particle flux at Earth resulting in visible meteors [2]. We simulate the dynamical evolution of these particles between the years 1780–2200 with a focus on potential meteor activity at Earth.

Our numerical simulation includes the major perturbing gravitational bodies (the Sun, Planets, Pluto, Ceres, Pallas, and Vesta) and solar radiation forces that are applicable to our particle’s size range [1]. We use REBOUND [3], an orbital integration API augmented with REBOUNDx [4] to include solar radiation pressure and Poynting-Robertson drag in our n-body numerical integrations. Our simulations release particles from Bennu at a regular rate (600 grams per week) throughout its orbit with a size distribution based on OSIRIS-REx mission observations [5]. We then evolve the orbits forward in time, examining the population of particles each year when the Earth is nearest to Bennu’s orbit. Simulated impact events inform our conclusions on annual particle flux rate measurements at Earth.

1. D.S. Lauretta and C.W. Hergenrother et al. (2019). Science 366, 1217-1227

2. Q. Ye (2019) Research Notes of the AAS 3, 56.

3. H. Rien and S.F. Liu (2012) Astronomy & Astrophysics 537, A128.

4. Tamayo, Daniel, et al. (2020) Monthly Notices of the Royal Astronomical Society 491.2

5. S.R. Chesley et al. (2020) JGR Planets 125, e2019JE006363