Definitions

Corot

Corot

[kaw-roh, kuh-; Fr. kaw-roh]
Corot, Jean-Baptiste Camille, 1796-1875, French landscape painter, b. Paris. Corot was one of the most influential of 19th-century painters. The son of shopkeepers, he worked in textile shops until 1822, when he began to study painting. The classical landscape painters Michallon and Bertin were his teachers. In 1825 he made his first trip to Italy, during which he painted calm, solid, and exquisitely composed groups of Roman buildings (e.g., View of the Farnese Gardens, 1826; Phillips Coll., Washington, D.C.). Upon his return to France he lived mostly in the Ville d'Avray, which formed the subject of many of his celebrated paintings, including two in the Metropolitan Museum. He worked in Italy again in 1834 and 1843, and traveled in Switzerland, Holland, and England. Corot exhibited regularly at the Salon from 1827. Corot's landscapes celebrate the countryside without idealizing the peasant or romanticizing farm labor. He used sketches made directly from nature to aid his studio compositions, sometimes painting entire landscapes outdoors. In Rome he created works notable for their simplicity of form and clarity of lighting, such as the Colisseum and the Forum (both: Louvre). His later landscapes, more lyrical in tone and painted primarily in shades of gray and green, were more popular. His delicate handling of light is especially evident in Femme à la Perle (Louvre) and Interrupted Reading (Art Inst., Chicago). His work is represented in most of the prominent galleries of England, France, and the United States.

See studies by J. Leymarie (tr. 1966) and Y. Taillandier (tr. 1967).

COROT (COnvection ROtation and planetary Transits) is a space mission led by the French Space Agency (CNES) in conjunction with the European Space Agency (ESA) and other international partners. The mission has two objectives: to search for extrasolar planets with short orbital periods, particularly those of large terrestrial size, and to perform asteroseismology by measuring solar-like oscillations in stars. It was launched at 14:28 GMT on December 27, 2006, atop a Soyuz 2.1b carrier rocket. COROT subsequently reported first light on January 18, 2007 It is the first mission of its kind. It detected its first extrasolar planet, COROT-Exo-1b, in May 2007.

Overview

COROT consists of a 27 cm (10.6 inch) diameter afocal telescope with an array of spectroscopic detectors. The satellite, built in the Cannes Mandelieu Space Center, has a launch mass of 630 kg, is 4.10 metres long, 1.984 metres in diameter and is powered by two solar panels . A Russian Soyuz 2-1B rocket lifted the satellite into a circular polar orbit with an altitude of 827 km on 27 December 2006. The first scientific observation campaign started on February 3 2007.

Over its planned 2½ year mission it will observe perpendicular to its orbital plane, meaning there will be no Earth occultations, allowing 150 days of continuous observation. During the northern summer it will observe in an area around Serpens Cauda and during the winter it will observe in Monoceros. During the remaining 30 days between the two main observation periods, COROT will observe 5 other patches of sky.

The probe will monitor the brightness of stars, watching for the slight dimming that happens in regular intervals when planets transit their primary sun. COROT will be sensitive enough to detect rocky planets several times larger than Earth; it is also expected to discover new gas giants, which currently comprise almost all of the known extrasolar planets.

COROT will also undertake asteroseismology. It can detect luminosity variations associated with acoustic pulsations of stars. This phenomenon allows calculation of a star's precise mass, age and chemical composition and will aid in comparisons between the sun and other stars.

In each field of view there will be one main target star for the asteroseismology as well as up to nine other targets. Simultaneously, it will be recording the brightness of 12,000 stars brighter than apparent magnitude 15.5 for the extrasolar planet study. It is expected that a few dozen planets will be found as a result of this project.

Development

The primary contractor for the construction of the COROT vehicle was CNES, to which individual components were delivered for vehicle assembly. The COROT equipment bay, which houses the data acquisition and pre-processing electronics, was constructed by the LESIA Laboratory at the Paris Observatory and took 60 man-years to complete. The COROT camera, also constructed by the LESIA Laboratory, took 25 person-years to complete.

Potential

Before the beginning of the mission, the team stated with caution that COROT would only be able to detect planets a few times to several times larger than Earth and that it was not specifically designed to detect habitable planets (it would instead assess their potential for habitability). According to the press release announcing the first results, COROT's instruments are performing with higher precision than had been predicted, and may be able to find planets down to the size of Earth.

COROT should be assumed to only detect a small percentage of planets within its detection range due to the low percentage of existing planets that would likely make transits from the angle of observation from our Solar System. Expectations are that any planetary systems detected within a suitable range for further observations will be followed up by the future Darwin and Terrestrial Planet Finder spacecrafts or other projects like Kepler (NASA), New Worlds Mission, or Space Interferometry Mission.

Discoveries

On May 3, 2007, it was reported that COROT had discovered a 'hot Jupiter' COROT-Exo-1b orbiting a sun-like star 1,500 light years away. This planet has a radius approximately 1.78 times that of Jupiter, a mass approximately 1.3 times that of Jupiter, and orbits its parent star once every 1.5 days. On the 300th day of operations ESA reported that "CoRoT is discovering exo-planets at a rate only set by the available resources to follow up the detections". On December 20, 2007, additional results were published, declaring that a second exoplanet, COROT-Exo-2b had been discovered, this time with a radius 1.4 times and a mass 3.5 times that of Jupiter. The orbital period is less than two days. Results on asteroseismology were published in the same press release. Three papers describing the two exoplanets, with radial-velocity follow-up, appeared in Astronomy and Astrophysics in May 2008 (Barge 2008, Alonso 2008 and Bouchy 2008).

In May 2008, findings of two new exoplanets, as well as an unknown celestial object COROT-Exo-3b were announced by ESA. COROT-Exo-3b appears to be "something between a brown dwarf and a planet." In addition COROT has detected a faint signal, which could be another exoplanet with a radius as small as 1.7 Earth's radius. The existence of this object, which could be a rocky exoplanet, has not been confirmed yet.

See also

References

Further reading

Overviews in the popular press

Mission pages

Peer-reviewed manuscripts: COROT discoveries

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