Radar imaging of Toutatis
Asteroid Toutatis, number 4179, was very recently discovered as far as asteroids go. The asteroid was discovered by C. Pollas on January 4, 1989, at Caussols, France. Images of asteroid Toutatis show that there are two irregular S-type asteroids that are in contact with each other.
These “contact binaries” may be common. The asteroid Toutatis is not the first one discovered. The two bodies are 4 km and 2.5 km in diameter, respectively. They were measured during a close approach to Earth (4million km) by the Goldstone Deep Space Communications Complex. A 400,000-watt coded radio transmission was beamed at Toutatis. The signals returned in as little as 24 seconds. Toutatis has several features that seem to show a series of impact events during its history. The impact craters and the fact that it is a contact binary may show proof of an small accretion in its past.
The asteroid Toutatis is one of the strangest objects in space in respect to its axial rotation. Most asteroids and planets rotate on a single axis and move like a perfect spiral pas. Toutatis wobbles like a lame duck pass because of the two objects. One consequence of this strange rotation is that Toutatis does not have a fixed north pole like the Earth. Its north pole wanders along a curve on the asteroid. The stars would never be in the same place twice if they were to be observed from Toutatis.
The asteroid Toutatis will pass by Earth, On September 29, 2004, at a range of four times the distance between the Earth and the Moon. That will be the closest approach of any known asteroid or comet between now and the year 2060. A consequence of the asteroid’s frequent close approaches to Earth is that its trajectory cannot be predicted accurately for more than a few centuries. Of all the Earth-crossing asteroids, the orbit of Toutatis is thought to be one of the most chaotic.
The asteroid Toutatis is one of the most interesting small asteroids in the solar system just because of it eccentric orbit and close approaches to Earth. The way it was studied by sound waves is also very interesting. Perhaps more will be learned about Toutatis on its next approach to Earth.
We have written a few articles about Toutatis for Universe Today. Here’s an article about a time that Toutatis came close to the Earth. And here’s another article when it was safely past us.
Want more resources on asteroids? Here’s some Toutatis information from Solarviews, and here’s NASA’s information page on Toutatis.
We have recorded two episodes of Astronomy Cast about asteroids. There’s Episode 55: The Asteroid Belt, and here’s Episode 29: Asteroids Make Bad Neighbors.
Reference:
NASA: Asteroid Toutatis
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