Abstract
From the MPC catalogue There were selected asteroid which can approach to the Earth (NEAs) with perihelion distances q < 1.3 AU. The total asteroid quantity was 7800 by the beginning of 2012. In order to estimation of all existing NEA's quantity a power-law for asteroid size distribution was used. An approximate formula for calculating of the asteroid size D by on the absolute magnitude H was used as well. It was obtained that all existing NEAs with з H < 16m (D > 2.5 km) may be considered as opened by today. The number of existing NEAs with D > 1 km should be about 2000. This number is almost twice the number of asteroids that are open today. Spatial orbit distributions for NEAs of different sizes around the Earth's orbit at different ecliptic longitudes λ (different seasons) were constructed. The most orbit quantities passes near the Earth's orbit at λ = 90° - 140° (August–October). It is about 30% higher than the minimum value at λ = 90° - 140° (December–January). About 150 asteroids with sizes greater than 1 km and about 150 000 asteroids with sizes greater than 100 m passes near the Earth's orbit at a distance of less than 0.2 AU in average during a year.
Keywords: asteroid dynamics; near-Earth space
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