Context. Since 1998, a planet-search around main sequence stars within 50 pc in the southern hemisphere has been underway with the CORALIE spectrograph at La Silla Observatory. Aims. With an observing time span of more than 20 yr, the CORALIE survey is able to detect long-term trends in data with masses and separations large enough to select ideal targets for direct imaging. Detecting these giant companion candidates will allow us to start bridging the gap between radial-velocity-detected exoplanets and directly imaged planets and brown dwarfs. Methods. Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of massive planetary companions and brown dwarfs on long-period orbits. Results. In this paper, we report the discovery of new companions orbiting HD 181234, HD 13724, HD 25015, HD 92987 and HD 50499. We also report updated orbital parameters for HD 50499b, HD 92788b and HD 98649b. In addition, we confirm the recent detection of HD 92788c. The newly reported companions span a period range of 15.6–40.4 yr and a mass domain of 2.93–26.77 MJup, the latter of which straddles the nominal boundary between planets and brown dwarfs. Conclusions. We report the detection of five new companions and updated parameters of four known extrasolar planets. We identify at least some of these companions to be promising candidates for imaging and further characterisation.

Context. The study of Earth-mass extrasolar planets via the radial-velocity technique and the measurement of the potential cosmological variability of fundamental constants call for very-high-precision spectroscopy at the level of δλ/λ < 10 −9 . Only an accurate wavelength calibration of the spectrograph can guarantee that the aimed precision is achieved over a multi-exposure and multi-epoch data set. Wavelength accuracy is obtained by providing two fundamental ingredients: 1) an absolute and information-rich wavelength source and 2) the ability of the spectrograph and its data reduction of transferring the reference scale (wavelengths) to a measurement scale (detector pixels) in a repeatable manner. Aims. The goal of this work is to improve the wavelength calibration accuracy of the HARPS spectrograph by combining the absolute spectral reference provided by the emission lines of a thorium-argon hollow-cathode lamp (HCL) with the spectrally rich and precise spectral information of a Fabry-Pérot-based calibration source. Methods. On the basis of calibration frames acquired each night since the Fabry-Pérot etalon was installed on HARPS in 2011, we construct a combined wavelength solution which fits simultaneously the thorium emission lines and the Fabry-Pérot lines. The combined fit is anchored to the absolute thorium wavelengths, which provide the "zero-point" of the spectrograph, while the Fabry-Pérot lines are used to improve the (spectrally) local precision. The obtained wavelength solution is verified for auto-consistency and tested against a solution obtained using the HARPS Laser-Frequency Comb (LFC). Results. The combined thorium+Fabry-Pérot wavelength solution shows significantly better performances compared to the thoriumonly calibration. In both cases, the residuals of the LFC line positions to the fitted wavelength solution follow a Gaussian distribution with an rms value of about 14 m s −1 for the combined solution, and twice as large for the thorium-only solution (29 m s −1 ). Given these positive results, we have applied the new calibrations to scientific frames and tested the radial-velocity residual on three well-known stars: HD 10700, HD 20794 and HD 69830. In all three cases the RV scatter could be reduced compared to the measurements using the previous calibration.Conclusions. The richness of the Fabry-Pérot spectrum helps improving the wavelength calibration using thorium-argon lamps or extending the wavelength domain of LFCs with limited operational range. The presented techniques will therefore be used in the new HARPS and HARPS-N pipeline, and will be exported to the ESPRESSO spectrograph.

Context. The field of exoplanet research is moving towards the detection and characterization of habitable planets. These exo-Earths can be easily found around low-mass stars by using either photometric transit or radial-velocity (RV) techniques. In the latter case the gain is twofold because the signal induced by the planet of a given mass is higher due to the more favourable planet-star mass ratio and because the habitable zone lies closer to the star. However, late-type stars emit mainly in the infrared (IR) wavelength range, which calls for IR instruments. Aims. SPIRou is a stable RV IR spectrograph addressing these ambitious scientific objectives. As with any other spectrograph, calibration and drift monitoring is fundamental to achieve high precision. However, the IR domain suffers from a lack of suitable reference spectral sources. Our goal was to build, test and finally operate a Fabry-Pérot-based RV-reference module able to provide the needed spectral information over the full wavelength range of SPIRou. Methods. We adapted the existing HARPS Fabry-Pérot calibrator for operation in the IR domain. After manufacturing and assembly, we characterized the FP RV-module in the laboratory before delivering it to the SPIRou integration site. In particular, we measured finesse, transmittance, and spectral flux of the system. Results. The measured finesse value of F = 12.8 corresponds perfectly to the theoretical value. The total transmittance at peak is of the order of 0.5%, mainly limited by fibre-connectors and interfaces. Nevertheless, the provided flux is in line with the the requirements set by the SPIRou instrument. Although we could test the stability of the system, we estimated it by comparing the SPIRou Fabry-Pérot with the already operating HARPS system and demonstrated a stability of better than 1 m s −1 during a night. Conclusions. Once installed on SPIRou, we will test the full spectral characteristics and stability of the RV-reference module. The goal will be to prove that the line position and shape stability of all lines is better than 0.3 m s −1 between two calibration sequences (typically 24 hours), such that the RV-reference module can be used to monitor instrumental drifts. In principle, the system is also intrinsically stable over longer time scales such that it can also be used for calibration purposes.