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Understanding the distribution of near-earth asteroids
1Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853-6801, USA. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. Observatoire de la Cote d'Azur, Boite Postale 4229, 06034 Nice C.
Science (New York, N.Y.)
|June 24, 2000
Summary
Researchers predict about 900 kilometer-sized near-Earth asteroids (NEAs), with 40% discovered. Many remaining NEAs are hard to detect due to their orbits.
Area of Science:
- Astronomy and Astrophysics
- Planetary Science
- Orbital Dynamics
Background:
- Near-Earth asteroids (NEAs) pose potential impact risks and are key to understanding solar system evolution.
- Current catalogs of NEAs are incomplete, particularly for smaller or dynamically distinct populations.
Purpose of the Study:
- To determine the orbital and size distributions of NEAs.
- To estimate the total population of kilometer-sized NEAs and assess the completeness of current surveys.
Main Methods:
- Numerical integration of NEAs from source regions to observed orbits.
- Estimation of observational biases and size distributions for asteroids in various orbits.
- Development of a model population to fit known NEA data.
Main Results:
- An estimated 900 NEAs with absolute magnitude < 18 (kilometer-sized) exist.
- Approximately 29% of these reside on Amor orbits, 65% on Apollo, and 6% on Aten orbits.
- An estimated 40% of kilometer-sized NEAs have been discovered, with the remainder on difficult-to-detect orbits.
Conclusions:
- The current NEA population is significantly underestimated, especially for objects on eccentric and inclined orbits.
- Improved detection strategies are needed for NEAs residing in less accessible orbital regions.
- This study provides a more accurate census of potentially hazardous asteroids.
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