COROT: Hunting for Exoplanets by Means of Stellar Seismology
COROT stands for (CO)nvection, (RO)tation and planetary (T)ransits. The COROT satellite was launched in December of 2006. It is a space telescope designed to detect tiny repetitive changes of luminosity in nearby stars caused by exoplanetary transit. An exoplanet is a planet outside our Solar System. The term transit can be described as the micro-eclipses that occur when a planet moves in front of its parent star. The COROT space telescope project is led by by the Centre National d’Etudes Spatiales (CNES) in conjunction with the European Space Agency (ESA). COROT’s instrumentation possesses additional features that enable exploration of stellar inner structure via oscillations of a star’s surface—or stellar seismology. In addition to gas giants similar to Jupiter, COROT also detects smaller, rocky, earth-like (telluric) exoplanets. Although one telescope equipment failure has occurred with a resulting decrease in field of view, COROT is still functional—it still provides abundant data.
Artist’s Concept of COROT
Credit: CNES - D. Ducros
Discoveries from COROT
ESA announced three discoveries in May 2008, one of which is of a new object—something between a brown dwarf and a planet—named COROT-Exo-3B. It defies classification by current standards. It has nearly 22 times the mass of Jupiter, yet it is approximately the same size as Jupiter. One difficulty in classification is due to its nearness to its parent star. Brown dwarfs aren’t ordinarily found this close to another star. But If it is a planet, it would be the densest one known, with a density twice that of lead. Another COROT discovery is of three stars similiar to the Sun, possessing similar oscillations and similar surface granulation.
Yet another discovery of COROT made public in 2009 is of a very small exoplanet—the smallest planet found ouside our Solar System to date. The planet is 1.7 times the size of Earth and orbits a star similar to the Sun. However, it has a very high temperature. Of the more than 400 exoplanets discovered so far, very few have been small and most have been gas giants. This new planet orbits its star once every 20 hours and therefore it is located very close to its stellar parent. Scientists feel this is especially significant because it is the first time a rocky planet has been discovered.
The Future of COROT
Although damaged somewhat, the future of COROT appears bright. ESA on its website discusses the possibility that one of the planets, Corot-9b, may even contain liquid water. Whatever the case, it is clear that COROT will continue to gather a unique variety of data that strikes a responsive chord in the hearts of people—the search for planets other than our own.
References and Resources
Centre National D’Etudes Spatiales: COROT
ESA Space Science: COROT
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