  This paper is devoted to the dynamics of asteroid (196256) 2003 EH1 that
belongs to the Amor group. It is known that the asteroid 2003 EH1 is associated
with one of the main annual meteor showers the Quadrantids. In this work we
analyze the influence of various perturbing factors on the asteroid motion. The
perturbations estimation was done by five different methods based on the
nominal orbit evolution and the size of the initial confidence region. The most
significant influences on the dynamical evolution of 2003 EH1 are gravitational
forces from the Sun, major planets and the Moon, and the relativistic effects
(RE) of the Sun. Of less importance are the Earth, the Sun and Jupiter
oblateness; gravitational perturbations from Pallas, Ceres, Vesta and Pluto;
and the RE of planets, the Moon, and Pluto. The researches of chaoticity and
evolution of asteroid 2003 EH1 were examined by integrating its motion
equations along with 500 clones. The time interval (from 1000 to 4000 years)
has been determined by integration precision estimation. We calculated the mean
exponential growth factor of nearby orbits (MEGNO) and found that MEGNO less
than two only in the interval from 1700 to 2300. After 2300 year the MEGNO
parameter increases that indicates motion instability. It shows that the orbit
may be considered as regular on the time interval of 300 years from now, and as
chaotic outside this interval. The reason, as we suppose, is frequent close
approaches of the asteroid with Jupiter and the overlap of apsidal nodal
resonances.
