Corot

Corot is the first mission dedicated to the search of planets similar to our Earth. It is also the first step on the road to the search for life outside our Solar System, one of the most profound questions for mankind. Corot stands for 'Convection Rotation and Planetary Transits' which describes its mission. Corot is a French led observatory and was launched on 27 December 2006 from Baikonur Cosmodrome, Kazakhstan. Its brief is to discover rocky alien worlds. Some of them nearly as small as the Earth.

Name COROT stands for 'Convection Rotation and planetary Transits' which describes the scientific goals of the mission. 

Description COROT will be the first mission capable of detecting rocky planets, several times larger than Earth, around nearby stars. It will also be the first European mission to carry out asteroseismology, that is looking inside stars to discern their physics. It consists of a small (30-centimetre) space telescope.
Conclusion
The launch was a key milestone for the extrasolar planet search, which began in 1995 when Michel Mayor and Didier Queloz from the Geneva Observatory in Switzerland reported the first planet circling a Sun-like star. Since then, about 200 exoplanets (as at December 2006) have been found.

About Spacecraft

Corot uses a 30cm (12 inch) telescope to monitor thousands of stars looking for tiny dips in their brightness as a planet passes in front of, or ‘transits’, them. Corot’s observations and follow-up work by ground-based telescopes will allow astronomers to calculate the sizes, masses and densities of the planets. It should identify new gas giants along with rocky planets several times as massive as the Earth.

The rocky worlds likely to be found are those with orbits of 50 days or less, making them blisteringly hot. But if they circle a dim red dwarf, they might lie in the ‘habitable zone’ – a region cool enough for liquid water to form on the surface. So it may be possible to find a planet made almost solely of water.

As well as hunting for planets Corot will measure the subtle brightness changes in stars caused by sound waves resonating through them. This data will be used to probe their interiors, revealing their internal structures.

The Facts

Name:
Contributors: French National Space Agency (CNES), ESA, Austria, Spain, Germany, Belgium and Brazil.
Launch Date: 22 December 2006
Launch Site:.
Orbit: Polar circular orbit, altitude 896km (557 miles)
Mission Length: 2.5 years
Launch Vehicle: Soyuz Fregat
Launch Mass: 650kg (1430 lb)

How are planets detected?

Most extrasolar planets have been discovered indirectly because of their gravity makes their parent stars ‘wobble’ as the planets circle round them. The period and size of the wobble reveals the planet’s orbital period and minimum mass.

Does Corot measure Star Wobbles?
No. It takes a different approach, looking for planets that cross the face of their stars once during each orbit, making the stars dim. Most planets don’t appear to transit their stars when viewed from Earth – their orbits have to have a special alignment.

What’s the Benefit of Transits?
They reveal a wealth of information about a planet, including its diameter and sometimes hints about the chemistry of its atmosphere.

Will more Satellites hunt for Planets?
Yes. NASA plans to launch a mission in 2008 called Kepler to look for habitable Earth-lie planets. ESA hopes that from around 2015, its three Darwin spacecraft will image Earth-like worlds to look for signs of life.

Did you know?

Will more Satellites hunt for Planets?

Yes. NASA plans to launch a mission in 2008 called Kepler to look for habitable Earth-lie planets. ESA hopes that from around 2015, its three Darwin spacecraft will image Earth-like worlds to look for signs of life.

COROT will be the first mission capable of detecting rocky planets, several times larger than Earth, around nearby stars (planets outside our Solar System are referred to as ‘exoplanets’). It consists of a 30-centimetre space telescope. It will be launched in late 2006.

COROT will use its telescope to monitor closely the changes in a star’s brightness that comes from a planet crossing in front of it. While it is looking at a star, COROT will also be able to detect ‘starquakes’, acoustical waves generated deep inside a star that send ripples across a star’s surface, altering its brightness. The exact nature of the ripples allows astronomers to calculate the star's precise mass, age and chemical composition. 

This technique is known as asteroseismology and ESA’s Solar and Heliospheric Observatory (SOHO) has been taking similar observations of the Sun for years. The COROT data is therefore essential to compare the Sun with other stars.

Spacecraft

The payload of the COROT satellite consists of a telescope, two cameras - one for each of the two mission objectives (exoplanet search and asteroseismology), and the on-board computer processors. The latter were manufactured in ESA's European Space Research and Technology Centre (ESTEC) by the Research and Scientific Support Department as one contribution of ESA to the COROT mission.

The telescope is made out of two parabolic mirrors, having a 1.1-metre focal length. The field of view is a square of 2.8 x 2.8°, half for the seismology mission, the other half for the exoplanet mission. A prism, used by the telescope for certain aspects of the mission, will separate colours, enabling scientists to study stellar activity during a planetary transit.

There is an external ‘baffle’ on the telescope (designed at ESTEC). This is a device for shielding a lens from ‘light pollution’ from sources other than those objects at which the telescope is looking.

Journey

COROT was placed in a circular, polar orbit that allows for continuous observations of two large and opposite regions in the sky for more than 150 days each. Within each region there are many selected fields that will be monitored in turn. The reason for the oppositely sited regions is that, because of the Earth’s movement around the Sun, the sun’s rays start to interfere with the observations after 150 days. COROT then rotates by 180 degrees and start observing the other region.

History

COROT was first proposed in December 1996 by the French National Space Agency (CNES) and, over the next three years, the project was researched to see if it was feasible. In September 1999, a call for potential European partners was made and in March 2000, CNES gave the green light to carry out COROT. ESA (European Space Agency) joined the mission in October 2000 by agreeing to provide the optics for the telescope and to test the payload.

Through this collaboration a number of European Scientists have been selected as Co-Investigators in open competition. They come from Denmark, Switzerland, the UK and Portugal. The baffle of the telescope has also been developed by a team at ESA's European Space Research and Technology Centre (ESTEC). ESA’s Research and Scientific Support department (RSSD) at ESTEC is a full partner by providing the on-board Data Processing Units (DPU’s). Other partners in COROT are Austria, Spain, Germany, Belgium and Brazil. The ground stations used for COROT are located in Kiruna (S), Aussaguel (F) Hartebeesthoek (South Africa), Kourou (French Guyana), with mission specific ground stations in Alcantara (Brazil) and Vienna (A).

COROT was launched by a Soyuz rocket from the Baikonur cosmodrome in Kazakhstan on 27 December 2006. Settled in its almost-circular polar orbit ranging between 895 and 906 kilometres above the Earth's surface, the spacecraft was powered on on 2 January 2007 and started its science observations on 3 February this year.

Partnerships

COROT is a mission led by the French national space agency, CNES. ESA has joined the mission by providing the optics for the telescope and testing of the payload. Through this collaboration a number of European scientists have been selected as Co-Investigators in open competition. They come from Denmark, Switzerland, the UK and Portugal. As a result of ESA’s participation in COROT, scientists from ESA’s Member States will be given access to the satellite’s data. The baffle of the telescope has also been developed by a team at ESA’s ESTEC site. 

ESA’s Research and Scientific Support department (RSSD) at ESTEC is a full partner in COROT by providing the on-board Data Processing Units (DPU’s). Other partners in COROT are Austria, Spain, Germany, Belgium and Brazil. 

The ground stations used for COROT are located in Kiruna (S), Aussaguel (F) Hartebeesthoek (South Africa), Kourou (French Guyana), with mission-specific ground stations in Alcantara (Brazil) and Vienna (A). 

Searching for planets outside our Solar System and mapping the stellar interiors.

COROT, a CNES project with ESA participation, is a mission with a dual goal. It is the first space mission dedicated entirely to the search of extra-solar planets. It provides a wide-field survey of planets like our own at an unprecedented level of accuracy. It is also making the most comprehensive study ever of the interior of stars other than our Sun. Both objectives are achieved by analysing the behaviour of light emitted by a target star.

An exoplanet is detected by COROT due to a sudden decrease in the intensity of light or the 'light curve' of a parent star when a planet transits in front of it.
The study of stellar interiors - or 'asteroseismology' - is carried out by analysing the oscillations in the light curve of the star. The oscillations are created due to mechanical waves propagating in the star itself and they give a clue to the structure of its interior.

COROT's strength lies in the continued observation of the same targets in a given area of the sky. The observations have been on since the science operations began, 60 days ago. Another strong point is the accuracy with which it measures the variations in the luminosity of the star.

The first planet detected by COROT, now named 'COROT-Exo-1b', is a very hot gas giant, with a radius equal to 1.78 times that of Jupiter. It orbits a yellow dwarf star similar to our Sun with a period of about 1.5 days. 'COROT-Exo-1b' is situated roughly 1500 light years from us, in the direction of the constellation Unicorn (Monoceros). Coordinated spectroscopic observations from the ground have also allowed the determination of the mass of the planet, equivalent to about 1.3 Jupiter masses.
 

is the first mission dedicated to the search of planets similar to our Earth. It is also the first step on the road to the search for life outside our Solar System, one of the most profound questions for mankind. Corot stands for 'Convection Rotation and Planetary Transits' which describes its mission. Corot is a French led observatory and launched on 27 December 2006 from  Baikonur Cosmodrome, Kazakhstan. Its brief is to discover rocky alien worlds. Some of them nearly as small as the Earth.

This is an artist¹s impression of a Jupiter-sized planet passing in front of its parent star. Credits: NASA, ESA and G. Bacon