522 Helga
Encyclopedia
522 Helga is a minor planet
orbiting the Sun
. It is notable for being the first such object to be shown to be in a stable but chaotic
orbit in resonance
with Jupiter
, its Lyapunov time
being relatively short, at 6,900 yr. Despite this, its orbit appears to be stable, as the eccentricity
and precession
rates are such that it avoids close encounters with Jupiter. http://www.nature.com/nature/journal/v357/n6379/abs/357569a0.html
Minor planet
An asteroid group or minor-planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid...
orbiting the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. It is notable for being the first such object to be shown to be in a stable but chaotic
Chaos theory
Chaos theory is a field of study in mathematics, with applications in several disciplines including physics, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions, an effect which is popularly referred to as the...
orbit in resonance
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
with Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, its Lyapunov time
Lyapunov exponent
In mathematics the Lyapunov exponent or Lyapunov characteristic exponent of a dynamical system is a quantity that characterizes the rate of separation of infinitesimally close trajectories...
being relatively short, at 6,900 yr. Despite this, its orbit appears to be stable, as the eccentricity
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
and precession
Precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
rates are such that it avoids close encounters with Jupiter. http://www.nature.com/nature/journal/v357/n6379/abs/357569a0.html