Dynamical erosion of the asteroid belt and implications for large impacts in the inner Solar System

By D. Minton, R. Malhotra. 2009

162 citations recorded by the source corpus.

Abstract The cumulative effects of weak resonant and secular perturbations by the major planets produce chaotic behavior of asteroids on long timescales. Dynamical chaos is the dominant loss mechanism for asteroids with diameters D ≳ 10 km in the current asteroid belt. In a numerical analysis of the long-term evolution of test particles in the main asteroid belt region, we find that the dynamical loss history of test particles from this region is well described with a logarithmic decay law. In our simulations the loss rate function that is established at t ≈ 1 Myr persists with little deviation to at least t = 4 Gyr . Our study indicates that the asteroid belt region has experienced a significant amount of depletion due to this dynamical erosion—having lost as much as ∼50% of the large asteroids—since 1 Myr after the establishment of the current dynamical structure of the asteroid belt. Because the dynamical depletion of asteroids from the main belt is approximately logarithmic, an equal amount of depletion occurred in the time interval 10–200 Myr as in 0.2–4 Gyr, roughly ∼30% of the current number of large asteroids in the main belt over each interval. We find that asteroids escaping from the main belt due to dynamical chaos have an Earth-impact probability of ∼0.3%. Our model suggests that the rate of impacts from large asteroids has declined by a factor of 3 over the last 3 Gyr, and that the present-day impact flux of D > 10 km objects on the terrestrial planets is roughly an order of magnitude less than estimates currently in use in crater chronologies and impact hazard risk assessments.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/1a5ab85d02fd924c37bc5e005bb464a039438feb

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Citations in the corpus

THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS (2012, background): “Minton & Malhotra (2010) also found that between 1-4 Gyr, roughly 0.4% of asteroids in their simulations impacted the Sun, suggesting that even at later times, a significant flux of asteroids can be tidally disrupted.”
EVIDENCE FROM THE ASTEROID BELT FOR A VIOLENT PAST EVOLUTION OF JUPITER's ORBIT (2010, methodology): “…- 8 Se p 20 10 To translate these collision probabilities into estimatesof the total mass impacting the Earth-Moon system, we take into account that Minton & Malhotra (2010) argued that the asteroid belt might have lost half of its population during the last 3.5 Gy because of chaotic diffusion.”
Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion (2017, background): “…and Franklin, 1997; Nagasawa et al., 2000; Zheng et al., 2017), chaotic excitation (Izidoro et al., 2016), an instability in the giant planets’ orbits (Morbidelli et al., 2010), and long-term dynamical effects (Minton and Malhotra, 2010) may have contributed to shaping the present-day distribution.”