* Astronomy

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RE: Corot Space Telescope

Blobrana · L

Exoplanet hunter nears its end

A pioneering European space telescope that discovered the first rocky extrasolar planet is on its last legs, Nature has learned.
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Title: An analysis of CoRoT multicolour photometry of exoplanets
Authors: F. Borsa, E. Poretti

We analysed the chromatic data of the planetary transits observed with CoRoT to supply homogeneous time series in each of the CoRoT colours. In a first step, we cleaned the chromatic light curves from the contamination of nearby stars and removed outliers and trends caused by anything different from the planetary transits. Then, we simultaneously fitted the chromatic transits of each planet, obtaining a common solution for the orbital parameters i, t0 and a/Rs, with a particular care in the fitting for different limb-darkening parameters. The planet-to-star radius ratios in the CoRoT colours are compatible when considering one planet at a time, but the ensemble of low-mass planets seems to show a peculiar behaviour of the radius ratios.

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Corot telescope in exoplanet haul

Ten new planets outside our Solar System have been spotted by the French-led Corot satellite, bringing the total number of known exoplanets to 561.
They include one planet orbiting an unusually young star, and two Neptune-sized planets orbiting the same star.
Corot, launched in 2006, spots planets by measuring the tiny dip in stellar light that occurs when planets pass between the stars and the Earth.
It has now added 23 planetary systems to the ever-growing roster.
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Title: The CoRoT Exoplanet program : status & results
Authors: M. Deleuil, C. Moutou, P. Bordé, the CoRoT exoplanet science team

The CoRoT satellite is the first instrument hunting for planets from space. We will review the status of the CoRoT/Exoplanet program. We will then present the CoRoT exoplanetary systems and how they widen the range of properties of the close-in population and contribute to our understanding of the properties of planets.

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Blobrana · L

The CoRoT team have announced the discovery of six diverse new planets, from 'shrunken-Saturns' to 'bloated hot Jupiters' as well a very rare brown dwarf with 60 times the mass of Jupiter.

The six new planets are:

CoRoT-8b: the smallest in this batch: At about 70% of the size and mass of Saturn, CoRoT-8b is moderately small among the previously known transiting exoplanets. Its internal structure should be similar to that of ice giants, like Uranus and Neptune, in the Solar System. It is the smallest planet discovered by the CoRoT team so far after CoRoT-7b, the first transiting Super-Earth.

CoRoT-10b: the eccentric giant: The orbit of CoRoT-10b is so elongated that the planet passes both very close to and very far away from its star. The amount of radiation it receives from the star varies tenfold in intensity, and scientists estimate that its surface temperature may increase from 250 to 600°C, all in the space of 13 Earth-days (the length of the year on CoRoT-10b).

CoRoT-11b: the planet whose star does the twist: CoRoT-11, the host star of CoRoT-11b, rotates around its axis in 40 hours. For comparison, the Sun's rotation period is 26 days. It is particularly difficult to confirm planets around rapidly rotating stars, so this detection is a significant achievement for the CoRoT team.

CoRoT-12b, 13b and 14b: a trio of giants: These three planets all orbit close to their host star but have very different properties. Although CoRoT-13b is smaller than Jupiter, it is twice as dense. This suggests the presence of a massive rocky core inside the planet. With a radius 50% large than Jupiter's (or 16 times larger than the Earth's), CoRoT-12b belongs to the family of 'bloated hot Jupiters', whose anomalously large sizes are due to the intense stellar radiation they receive. On the other hand, CoRoT-14b, which is even closer to its parent star, has a size similar to Jupiter's. It is also massive, 7.5 times the mass of Jupiter, which may explain why it is less puffed up. Such very massive and very hot planets are rare, CoRoT-14b is only the second one discovered so far.

CoRoT-15b: the brown dwarf: CoRoT-15b's mass is about 60 times that of Jupiter. This makes it incredibly dense, about 40 times more so than Jupiter. For that reason, it is classified as a brown dwarf, intermediate in nature between planets and stars. Brown dwarfs are much rarer than planets, which makes this discovery all the more exciting.

Dr Suzanne Aigrain leads a team of UK researchers at the Universities of Oxford, Exeter and St Andrews who participate in the CoRoT exoplanet program. Their research is supported by the Science and Technology Facilities Research Council.

Source

Blobrana · L

CoRoT unveils a rich assortment of new exoplanets

By detecting the faint dimming in the light emitted by stars during a transit event, CoRoT has detected six new exoplanets - each with its own peculiar characteristics - and one brown dwarf. One of these exoplanets, designated CoRoT-11b, has twice the mass of Jupiter and orbits a rapidly rotating star; this type of star is an extremely difficult target for exoplanet searches and its detection marks a significant achievement for the CoRoT team.
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Florilège de planètes découvertes par le satellite CoRoT : 7 corps aux caractéristiques bien distincte

Aujourd'hui, l'équipe CoRoT annonce la découverte d'une naine brune et de six nouvelles exoplanètes aux caractéristiques très variées. CoRoT, satellite de l'Agence spatiale française (CNES), permet de découvrir des exoplanètes depuis l'espace, par la détection de leur passage devant leur étoile. L'observation de ces transits est relayée par des observations au sol, notamment avec les spectrographes HARPS de l'ESO et Sophie de l'INSU-CNRS: les astronomes obtiennent alors une mesure précise de la taille, de la masse et de l'orbite de ces nouvelles planètes, sans les voir directement. Elles sont ainsi les seules à permettre d'obtenir les informations les plus complètes sur leur nature et les modes de formation et d'évolution de ces nouveaux mondes.
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Title: CoRoT's first seven planets: An overview
Authors: R. Dvorak, J. Schneider, H. Lammer, P. Barge, G. Wuchterl, the CoRoT team
(Version v2)

The up to 150 day uninterrupted high-precision photometry of about 100000 stars - provided so far by the exoplanet channel of the CoRoT space telescope - gave a new perspective on the planet population of our galactic neighbourhood. The seven planets with very accurate parameters widen the range of known planet properties in almost any respect. Giant planets have been detected at low metallicity, rapidly rotating and active, spotted stars. CoRoT-3 populated the brown dwarf desert and closed the gap of measured physical properties between standard giant planets and very low mass stars. CoRoT extended the known range of planet masses down to 5 Earth masses and up to 21 Jupiter masses, the radii to less than 2 Earth radii and up to the most inflated hot Jupiter found so far, and the periods of planets discovered by transits to 9 days. Two CoRoT planets have host stars with the lowest content of heavy elements known to show a transit hinting towards a different planet-host-star-metallicity relation then the one found by radial-velocity search programs. Finally the properties of the CoRoT-7b prove that terrestrial planets with a density close to Earth exist outside the Solar System. The detection of the secondary transit of CoRoT-1 at the 10^{-5}-level and the very clear detection of the 1.7 Earth radii of CoRoT-7b at 3.5 10^{-4} relative flux are promising evidence of CoRoT being able to detect even smaller, Earth sized planets.

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CNES, together with its national partners (CNRS and Observatoire de Paris) and international partners (Austria, Germany, Belgium, Brazil, ESA, Spain), have extended the CoRoT mission for three more years, up to 31st March, 2013.
The decision was taken on the 23rd October this year.

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