Earth-crossing asteroids - Orbital classes, collision rates with earth, and originAsteroids that can intersect the orbit of the earth are discussed, which include Aten asteroids (semimajor axis (a) less than 1 AU, aphelion greater than 0.983 AU), Apollo asteroids (a greater than 1 AU, perihelion less than 1.017 AU), and Amor asteroids (perihelion distance between 1.017 and 1.3 AU). The principal sources of earth-crossing asteroids appear to be extinct comet nuclei and collision fragments from regions in the main asteroid belt. The total population of earth-crossers is estimated at 13,000, of which approximately 8% are Atens, 50% are Apollos, and 40% are Amors,and the present collision rate of such asteroids with the earth is estimated at about 3.5 objects, to absolute magnitude 18, per million years.
Document ID
19800040395
Acquisition Source
Legacy CDMS
Document Type
Other - Collected Works
Authors
Shoemaker, E. M. (California Inst. of Tech. Pasadena, CA, United States)
Williams, J. G. (California Inst. of Tech. Pasadena, CA, United States)
Helin, E. F. (California Inst. of Tech. Pasadena, CA, United States)
Wolfe, R. F. (California Institute of Technology Pasadena, Calif., United States)