Horseshoe orbit of Asteroid 2002 AA29
In the previous integration we observed
2002 AA29 in a 1:1 resonant
orbit with Earth. Here we see it again but the view has been modified so that Earth
is constantly in the same direction relative to the Sun. This is
achieved using rotating coordinates. You will notice that Earth moves
a little towards and away from the sun each year - this is because the
Earth's orbit is not perfectly circular.
By using tilt,
rotate and zoom controls you can
examine in more detail how the Asteroid reaches its nearest recent
approaches in 2003 and 2004.
Now reset the tilt so that the orbits
are about circular and zoom so that you
can see the entire orbit. Use the
speed control to speed up the integration
(so that display step is about 25 days) )and see how the Asteroid 'wiggles' steadily away from Earth. After
about 95 years it approaches Earth again from the other side. But it
DOES NOT OVERTAKE!. In fact it starts to wiggle back round in the
other direction. This movement backwards and forwards is called a
Horseshoe Orbit and it is quite often seen when two bodies have
orbits of a very similar period.
Capture of 2002 AA29
Continue with the integration running fast, through several
Horseshoe reversals, until about year 2560 then slow it down. From 2577 to 2622 the Asteroid appears to be
"captured" by Earth circling each year as a "pseudo satellite". You
can use the various controls (back, rotate,
tilt, orbit etc) to examine this event in detail.
Alternatively go to this simulation that
will show you the event in detail.
This integration includes Asteroid 2002 AA29 and all the main
bodies of the Solar System. Earth and 2002 AA29 are shown in their
normal colours while the others are shown faintly. Rotating
coordinates are used to keep the Earth approximately static although
it does wiggle a bit due to its slightly elliptical orbit.
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