| タイトル | Earth-crossing asteroids - Orbital classes, collision rates with earth, and origin |
| 著者（英） | Helin, E. F.; Williams, J. G.; Wolfe, R. F.; Shoemaker, E. M. |
| 著者所属（英） | California Inst. of Tech. |
| 発行日 | 1979-01-01 |
| 言語 | eng |
| 内容記述 | Asteroids 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. |
| NASA分類 | ASTRONOMY |
| レポートNO | 80A24565 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/422756 |
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