Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Several phenomena are known to affect line profiles in solar-type stars, among which stellar oscillations, granulation and magnetic activity through spots, plages and activity cycles. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact on spectroscopic measurements such as radial velocities, line bisectors and line shapes. Methods. We use data from the HARPS high-precision planet-search sample comprising 304 FGK stars followed over about 7 years. We obtain high-precision Ca II H&K chromospheric activity measurements and convert them to R ′ HK indices using an updated calibration taking into account stellar metallicity. We study R ′ HK variability as a function of time and search for possible correlations with radial velocities and line shape parameters.Results. The obtained long-term precision of ∼0.35% on S-index measurements is about 3 times better than the canonical Mt Wilson survey, which opens new possibilities to characterize stellar activity. We classify stars according to the magnitude and timescale of the Ca II H&K variability, and identify activity cycles whenever possible. We find that 39±8% of old solar-type stars in the solar neighborhood do not show any activity cycles (or only very weak ones), while 61±8% do have one. Non-cycling stars are almost only found among G dwarfs and at mean activity levels log R ′ HK < -4.95. Magnetic cycle amplitude generally decreases with decreasing activity level. A significant fraction of stars exhibit small variations in radial velocities and line shape parameters that are correlated with activity cycles. The sensitivity of radial velocities to magnetic cycles increases towards hotter stars, while late K dwarfs are almost insensitive. Conclusions. Activity cycles do induce long-period, low-amplitude radial velocity variations, at levels up to ∼25 m s −1 . Caution is therefore mandatory when searching for long-period exoplanets. However, these effects can be corrected to high precision by detrending the radial velocity data using simultaneous measurements of Ca II H&K flux and line shape parameters.

The debugIT project is a large-scale integrating project funded as part of the 7 th EU Framework Programme (FP7). The main objectives of the project are to build IT tools designed to have significant impacts on the monitoring and control of infectious diseases and antimicrobial resistances in Europe; this will be done by building a technical and semantic infrastructure able to a) share heterogeneous clinical data sets from different hospitals in different countries, with different languages and legislations; b) analyse large amounts of this clinical data with advanced multimedia data mining; c) apply the knowledge obtained for clinical decisions and outcome monitoring. The concepts and architecture underlying this project are discussed.

EBLM J0113+31 is moderately bright (V=10.1), metal-poor ([Fe/H] ≈−0.3) G0V star with a much fainter M dwarf companion on a wide, eccentric orbit (=14.3 d). We have used near-infrared spectroscopy obtained with the SPIRou spectrograph to measure the semi-amplitude of the M dwarf’s spectroscopic orbit, and high-precision photometry of the eclipse and transit from the CHEOPS and TESS space missions to measure the geometry of this binary system. From the combined analysis of these data together with previously published observations we obtain the following model-independent masses and radii: M1 = 1.029 ± 0.025M⊙, M2 = 0.197 ± 0.003M⊙, R1 = 1.417 ± 0.014R⊙, R2 = 0.215 ± 0.002R⊙. Using R1 and the parallax from Gaia EDR3 we find that this star’s angular diameter is θ = 0.0745 ± 0.0007 mas. The apparent bolometric flux of the G0V star corrected for both extinction and the contribution from the M dwarf (&lt;0.2 per cent) is ${\mathcal {F}}_{\oplus ,0} = (2.62\pm 0.05)\times 10^{-9}$ erg cm−2 s−1. Hence, this G0V star has an effective temperature Teff, 1 = 6124 K ± 40 K (rnd.) ± 10 K (sys.). EBLM J0113+31 is an ideal benchmark star that can be used for “end-to-end” tests of the stellar parameters measured by large-scale spectroscopic surveys, or stellar parameters derived from asteroseismology with PLATO. The techniques developed here can be applied to many other eclipsing binaries in order to create a network of such benchmark stars.

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Abstract. In this paper we present the global results of a HARPS-GTO program to search for planets orbiting a sample of metal-poor stars. The detection of several giant planets in long period orbits is discussed in the context of the metallicitygiant planet correlation.

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