A novel planet in our solar system?


Astronomers Michael Brown, from the California Institute of Technology at Pasadena, and Chadwick Trujillo made an important discovery from pictures taken on June 4th, 2002, using the Mt Palomar telescope located near San Diego. Further observations performed from the space telescope Hubble confirmed the size of the novel object.

It is an iced body with a ca. 1,280-km diameter (that is 1/10 of that of Earth) located at 1,600 billions km away from Pluto. "This is the most important discovery in the solar system since that of Pluto, some 72 years ago", said officials at NASA.


Quaoar, that's its name, is 6,109 km a way from Earth, at the border of our solar system, within the Kuiper belt, a zone that concentrates asteroids and comet nucleus, further away from Neptune orbit. Quaoar orbit is circular around the sun.

This belt may gather ten billions of objects, with at least a 1,5 km diameter, but also some much larger ones. "This discovery strengthen our hypothesis suggesting that there might be a bunch of objects the size of Pluto within the Kuiper belt", states astronomer David Jewitt, from the Hawaï University.

This celestial body is made of ice and rocks, and resembles a comet in terms of constitution, but it is a t least 100 millions times bigger volumewise. During the past 10 years, some 500 iced bodies were detected in this Kuiper belt.

Research performed on archived documents revealed that Quaoar could already be seen on pictures taken in 1982, "but it went unoticed", said Michael Brown. "It may have been detected easily 20 years ago".

As we discover more and more large objects in the Kuiper belt, the idea that Pluto is a planet gets weaker. Indeed, Pluto lies in the Kuiper belt, and it is regarded by numerous specialists as being only the largest body of this belt, and not a true planet. "If we spotted Pluto today, knowing what we know on other objects from the Kuiper belt, we most likely would not regard it as a planet", declared Michael Brown.

These results were released to the Public by the Pasadena CIT team, during a meeting of the American Astronomy Society held at Birmingham (Alabama).

NASA thinks of launching a probe to explore Pluto, Charon and at least one object in the Kuiper belt. The mission, termed "New Horizons" may be ready to leave Earth in 2006. It wold take some 10 years to reach Pluto... If it gets funded, a point that is not "granted" at all.

Transmitted and translated from French by Yves, Sci team.
October 2002
According to AFP and AP agencies 

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