[meteorite-list] Asteroid 4179 Toutatis to Pass Closely By Earth on September 29

[Ron Baalke]

http://neo.jpl.nasa.gov/news/news144.html

Asteroid (4179) Toutatis to Pass Closely By Earth on Wednesday, September 29, 2004.
Donald K. Yeomans and Paul W. Chodas
Near-Earth Object Program
September 27, 2004

Toutatis, a potato-shaped asteroid about 4.6 km (3 miles) in its longest 
extent, will pass within 1,550,000 km (961,000 miles) of the Earth's center 
on Wednesday, September 29, 2004 - reaching its closest approach at 
13:36:32 GMT (06:36:32 PDT).  This is roughly four times the distance from 
the Earth to the moon and closer than this asteroid has come to Earth since 
at least the twelfth century.  Toutatis will not pass this closely 
again for the next 500 years.  The passage is the closest Earth approach this 
century for a known asteroid of this size.  

Because of an extensive 
set of optical and radar observations, the orbit for Toutatis is one of the 
best determined of any asteroid and there is no chance that this object 
will collide with the Earth during this encounter - or any other encounter 
for at least 5 centuries.

With the help of Toutatis radar observations, a shape and rotation model 
for this object has been developed.  Details on this work by Steve Ostro, 
R. Scott Hudson and colleagues can be found at:

http://www.eecs.wsu.edu/~hudson/Research/Asteroids/4179/

Simulations of the asteroid's rotation in space can be found at:

http://reason.jpl.nasa.gov/~ostro/ToutatisHires.mov
http://reason.jpl.nasa.gov/~ostro/ToutatisHires.avi

[Diagram][Diagram]

The two diagrams above show the circumstance of the asteroid flyby of the 
Earth.  The first shows an oblique view of the flyby at the time of closest 
approach, with the Moon's orbit drawn in for scale.  Toutatis approaches 
the Earth from the right in this diagram, passing from outside the Earht's 
orbit to inside on a path that passes beneath 
the ecliptic plane (the plane of the Earth's orbit).  The second diagram is 
an edge-on view showing how Toutatis passes the Earth well under the 
ecliptic plane, which is shown as a straight line.  Again, the Moon's orbit 
is shown for scale; note that it is slightly inclined to the ecliptic plane.