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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)
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)
In 2009 we started, within the dedicated HARPS-Upgrade GTO program, an intense radial-velocity monitoring of a few nearby, slowly-rotating and quiet solar-type stars. The goal of this campaign is to gather, with high cadence and continuity, very-precise radial-velocity data in order to detect tiny signatures of very-low-mass stars potentially in the(More)
We report a spectroscopic orbit with period P = 3.52433 ± 0.00027 days for the planetary companion that transits the solar-type star HD 209458. For the metallicity, mass, and radius of the star we derive [Fe/H]= 0.00 ± 0.02, M * = 1.1 ± 0.1 M ⊙ , and R * = 1.3 ± 0.1 R ⊙. This is based on a new analysis of the iron lines in our HIRES template spectrum, and(More)
Exoplanets down to the size of Earth have been found, but not in the habitable zone--that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water-carbon life(More)
A 4 M J planet with a 15.8 day orbital period has been detected from very precise radial velocity measurements with the CORALIE echelle spectrograph. A second remote and more massive companion has also been detected. All the planetary companions so far detected in orbit closer than 0.08 AU have a parent star with a statistically higher metal content(More)
This paper summarizes the information gathered for 16 still unpublished exoplanet candidates discovered with the CORALIE echelle spectrograph mounted on the Euler Swiss telescope at La Silla Observatory. Amongst these new candidates, 10 are typical extrasolar Jupiter-like planets on intermediate-or long-Two of these stars are in binary systems. The next 3(More)
Aims. A major goal of our survey is to significantly increase the number of detected extra-solar planets in a magnitude-limited sample to improve our knowledge of their orbital elements distributions and thus obtain better constraints for planet-formation models. Methods. Radial-velocity data were taken at Haute-Provence Observatory (OHP, France) with the(More)
Context. Low-mass extrasolar planets are presently being discovered at an increased pace by radial velocity and transit surveys, opening a new window on planetary systems. Aims. We are conducting a high-precision radial velocity survey with the HARPS spectrograph which aims at characterizing the population of ice giants and super-Earths around nearby(More)
Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with(More)