Nuno Miguel Carvalho Santos

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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)
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)
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)
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)
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)
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)
With the goal of confirming the metallicity " excess " observed in stars with planetary mass companions, we have conducted a high-precision spectroscopic study of a " comparison " sample of dwarfs included in the CORALIE extra-solar planet survey (Santos, Israelian, & Mayor 2001). The targets were chosen following two basic criteria: they make part of a(More)
Antimicrobial peptides (AMPs) are important potential alternatives to conventional therapies against bacterial infections. rBPI(21) is a 21 kDa peptide based on the N-terminal region of the neutrophil bactericidal/permeability-increasing protein (BPI). This AMP possesses highly selective bactericidal effects on Gram-negative bacteria and have affinity for(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)
Over the last years, antimicrobial peptides (AMPs) have been the focus of intense research toward the finding of a viable alternative to current antifungal drugs. Defensins are one of the major families of AMPs and the most represented among all eukaryotic groups, providing an important first line of host defense against pathogenic microorganisms. Several(More)