In this paper we test the accuracy of proper elements and proper frequencies computed for near-Earth asteroids (NEAs) by a semianalytic method with the planets on circular and coplanar orbits. These elements are compared with the ones computed by pure numerical integrations in the same reference frame and in a more realistic planetary system that takes into account the eccentricity and the inclination of the planets. To check the validity of the semianalytic method for the different kinds of existing dynamical behaviors, a fairly representative sample of NEAs has been investigated. These objects have different dynamical behaviors and have been chosen among the two categories of !-librating and !-circulating asteroids, ! being the argument of perihelion; to give a general idea of the validity of the semianalytic theory, the mean orbit of a meteor stream is included in our tests. We have then developed a procedure which allows the comparison between the outputs of the two methods. Given the required accuracy, this comparison appears satisfying, apart from a few cases for which the theory is known not to be valid. Therefore, the semianalytic method can already be used to compute proper elements and frequencies of known NEAs in a reliable way, though some improvements will be needed to account for the eccentricities and inclinations of the planets in the planetary system used for the computation.
Secular Orbital Evolution, Proper Elements, and Proper Frequencies for Near-Earth Asteroids: A Comparison between Semianalytic Theory and Numerical Integrations
GRONCHI, GIOVANNI FEDERICO;
2001-01-01
Abstract
In this paper we test the accuracy of proper elements and proper frequencies computed for near-Earth asteroids (NEAs) by a semianalytic method with the planets on circular and coplanar orbits. These elements are compared with the ones computed by pure numerical integrations in the same reference frame and in a more realistic planetary system that takes into account the eccentricity and the inclination of the planets. To check the validity of the semianalytic method for the different kinds of existing dynamical behaviors, a fairly representative sample of NEAs has been investigated. These objects have different dynamical behaviors and have been chosen among the two categories of !-librating and !-circulating asteroids, ! being the argument of perihelion; to give a general idea of the validity of the semianalytic theory, the mean orbit of a meteor stream is included in our tests. We have then developed a procedure which allows the comparison between the outputs of the two methods. Given the required accuracy, this comparison appears satisfying, apart from a few cases for which the theory is known not to be valid. Therefore, the semianalytic method can already be used to compute proper elements and frequencies of known NEAs in a reliable way, though some improvements will be needed to account for the eccentricities and inclinations of the planets in the planetary system used for the computation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
