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Efficient disruption of small asteroids by Earth's atmosphere
1Department of Earth Science and Engineering, Exhibition Road, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. p.a.bland@imperial.ac.uk
Nature
|July 18, 2003
Summary
A new separated-fragments model shows larger stony asteroids can break up in the atmosphere. This research clarifies the impact rate of small asteroids on Earth, estimating impacts for bodies over 220m occur every 170,000 years.
Area of Science:
- Planetary Science
- Astrophysics
- Geophysics
Background:
- Accurate modeling of bolide-atmosphere interactions is vital for predicting Earth impact rates.
- Previous models often simplified impactors as liquid-like ('pancake' models).
- A more realistic separated-fragments model accounts for individual particle motion, aerodynamics, and ablation.
Purpose of the Study:
- To compare 'pancake' and separated-fragments models for atmosphere-bolide interactions.
- To statistically analyze atmospheric disruption of iron and stony bolides up to 1 km.
- To determine the flux of small asteroids impacting Earth's surface.
Main Methods:
- Conducted over 1,000 simulations using both 'pancake' and separated-fragments models.
- Simulated iron and stony bolides with initial diameters up to approximately 1 km.
- Integrated simulation data with pre-atmospheric asteroid flux data.
Main Results:
- The separated-fragments model predicts atmospheric disruption of significantly larger stony bodies than previously estimated.
- The study provides a statistical picture of atmosphere-bolide interactions for various asteroid compositions and sizes.
- A dataset of over 1,000 simulated impacts was generated.
Conclusions:
- The separated-fragments model offers a more realistic assessment of bolide atmospheric entry.
- Earth's surface impact flux for small bolides (<1 km) has been elucidated.
- Asteroids larger than 220 m are estimated to impact Earth approximately every 170,000 years.
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