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A decade ago, the detection of the first transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres. Because such characterization studies are feasible only for transiting systems that are both nearby and for which the planet-to-star radius ratio is(More)
We present here the discovery and characterisation of a very light planet around HD 4308. The planet orbits its star in 15.56 days. The circular radial-velocity variation presents a tiny semi-amplitude of 4.1 ms −1 that corresponds to a planetary minimum mass m 2 sin i = 14.1 M ⊕ (Earth masses). The planet was unveiled by high-precision radial-velocity(More)
Among the 160 known exoplanets, mainly detected in large radial-velocity surveys, only 8 have a characterization of their actual mass and radius thanks to the two complementary methods of detection: radial velocities and photometric transit. We started in March 2004 an exoplanet-search programme biased toward high-metallicity stars which are more frequently(More)
This Letter reports on the photometric detection of transits of the Neptune-mass planet orbiting the nearby M-dwarf star GJ 436. It is by far the closest, smallest and least massive transiting planet detected so far. Its mass is slightly larger than Neptune's at M = 22.6 ± 1.9 M⊕. The shape and depth of the transit lightcurves show that it is crossing the(More)
The GJ 581 planetary system was already known to harbour three planets, including two super-Earths planets which straddle its habitable zone. We report here the detection of an additional planet – GJ 581e – with a minimum mass of 1.9 M ⊕. With a period of 3.15 days, it is the innermost planet of the system and has a ∼5% transit probability. We also correct(More)
The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed. Together with radial velocity measurements, this has led to a determination of the planet's radius and mass, confirming it to be a gas giant. But despite numerous searches for an atmospheric signature, only the dense lower atmosphere of(More)
We report the detection of 3 new planetary companions orbiting the solar-type stars GJ 3021, HD 52265 and HD 169830 using radial-velocity measurements taken with the CORALIE echelle spectrograph. All these planetary companions have longer orbital periods than the 51 Peg-like objects. The orbits are fairly eccentric. The minimum masses of these planets range(More)
The mass distribution of substellar companions exhibits a steep rise for masses below 5 MJ. Thus, the 14 companions having Msin i = 0.5 { 5 MJ are considered the best candidate planets around main sequence stars. The occurrence of such planets within 3 AU is 4%, but 2/3 of them orbit within just 0.3 AU. This \pile up" of planets near stars suggests that(More)