An artist's idea of ​​the transit of a "hot Jupiter" in front of his home star. Image: NASA, ESA and G. Bacon
The results of the space telescope Corot, which seeks to detect earth-like planets in foreign solar systems, surpass the expectations of the scientists involved. "Some of the instruments on board work much better than expected, " says Project Manager Malcolm Fridlund from Esa. Only sixty days after the beginning of the scientific measurements in early February, so to speak still in the test phase, Corot already discovered his first exoplanet. The object named "Corot-Exo-1b" is a so-called "hot Jupiter", a gas planet orbiting its star at close range. According to the Esa, its diameter is almost twice as large as that of Jupiter, its mass is 1.3 times. The exoplanet is located 1, 500 light-years from Earth and circles its sun every one and a half days.

Corot-Exo-1b is thus a typical representative of the slightly more than two hundred previously known exoplanets. Nevertheless, the Esa researchers are excited about the data of the space telescopes launched into orbit at the end of December 2006. "We still present raw data today, but they are extraordinary, " says Fridlund. After viewing the first data, he and his colleagues assume that Corot can track down rock formations the size of the earth and even determine the chemical composition of their atmosphere.

Corot, a joint mission of the Esa and the French space agency CNES, identifies planets by their shadow cast: If a planet passes by its sun, the luminosity of the star diminishes by a tiny fraction. Since the satellite keeps suspicious objects in sight for months, the measurements are extremely accurate. This way, even small exoplanets can be detected. Originally, the project team had assumed that a planet would be about three times the size of the Earth to be discovered by Corot. Meanwhile, the researchers even find it possible to track down distant twins of the earth. Under certain circumstances it would even be conceivable to catch starlight reflected by the exoplanets. That would provide information about the composition of the atmosphere.

The second task of Corot, to catch the vibrations of strange stars and to give an insight into their interior, masters the telescope with flying colors. In a sun-like star, which the telescope observed continuously for fifty days, Corot spotted large variations in brightness in a rhythm of several days. The measurements are exceptionally accurate, reports the Esa. "So far, the mission is under a good star, " says Fridlund, "after a perfect start and a premature start of the scientific measurements, we have been waiting eagerly for the first data. Now that we know their quality, we can expect great discoveries in the future. "Ad

Message from Esa Ute Kehse

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