Context. The TESS and PLATO missions are expected to find vast numbers of new transiting planet candidates. However, only a fraction of these candidates will be legitimate planets, and the candidate validation will require a significant amount of follow-up resources. Radial velocity (RV) follow-up study can be carried out only for the most

We report the discovery from K2 of two transiting hot Jupiter systems. K2-295 (observed in Campaign 8) is a K5 dwarf which hosts a planet slightly smaller than Jupiter, orbiting with a period of 4.0 d. We have made an independent discovery of K2-237 b (Campaign 11), which orbits an F9 dwarf every 2.2 d and has an inflated radius 60-70% larger than

We present precise photospheric parameters of 282 M dwarfs determined from fitting the most recent version of PHOENIX models to high-resolution CARMENES spectra in the visible (0.52-0.96 μm) and NIR wavelength range (0.96-1.71 μm). With its aim to search for habitable planets around M dwarfs, several planets of different masses have been detected

Ultra-hot Jupiters orbit very close to their host star and consequently receive strong irradiation, causing their atmospheric chemistry to be different from the common gas giants. Here, we have studied the atmosphere of one of these particular hot planets, MASCARA-2b/KELT-20b, using four transit observations with high resolution spectroscopy

We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R⊕ and an orbital period of Pb = 3.93 d. Precise stellar radial

Context. Although more than 2000 brown dwarfs have been detected to date, mainly from direct imaging, their characterisation is difficult due to their faintness and model-dependent results. In the case of transiting brown dwarfs, however, it is possible to make direct high-precision observations. Aims: Our aim is to investigate the nature and

Aims: Our scientific goal is to provide revised membership lists of the α Per, Pleiades, and Praesepe clusters exploiting the second data release of Gaia and produce five-dimensional maps (α, δ, π, μα cos δ, μδ) of these clusters. Methods: We implemented the kinematic method combined with the statistical treatment of parallaxes and proper motions

Warm, large exoplanets with 10–100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Although high eccentricity tidal migration has been invoked to explain their proximity to their host stars, a handful reside in or near orbital resonance with nearby planets, suggesting a gentler history of in

The search for Earth-like planets around late-type stars using ultrastable spectrographs requires a very precise characterization of the stellar activity and the magnetic cycle of the star, since these phenomena induce radial velocity (RV) signals that can be misinterpreted as planetary signals. Among the nearby stars, we have selected Barnard's

Although M dwarfs are known for high levels of stellar activity, they are ideal targets for the search of low-mass exoplanets with the radial velocity (RV) method. We report the discovery of a planetary-mass companion around LSPM J2116+0234 (M3.0 V) and confirm the existence of a planet orbiting GJ 686 (BD+18 3421; M1.0 V). The discovery of the

Context. Teegarden's Star is the brightest and one of the nearest ultra-cool dwarfs in the solar neighbourhood. For its late spectral type (M7.0 V), the star shows relatively little activity and is a prime target for near-infrared radial velocity surveys such as CARMENES. Aims: As part of the CARMENES search for exoplanets around M dwarfs, we

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the

Context. The study of young Sun-like stars is fundamental to understanding the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these phenomena in Sun-like stars. Aims: We present a new analysis of the entire Kepler photometric time series of the

Context. M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, but we are still lacking a consistent picture of the link between the magnetic fields and underlying dynamo mechanisms, rotation, and activity. Aims: In this work we aim to measure magnetic fields from the high-resolution near

Context. We study temporal variations of the emission lines of Hα, Hɛ, H and K CaII, D1 and D2 NaI, He4026, and He5876 in the HARPS spectra of Proxima Centauri across an extended time of 13.2 yr, from May 27, 2004 to September 30, 2017. Aims: We analyse the common behaviour and differences in the intensities and profiles of different emission lines

We demonstrate that the previously identified L/T transition brown dwarf SDSS J213154.43-011939.3 (SDSS 2131-0119) is a widely separated (82{^''.}3, ˜3830 au) common proper motion companion to the low-mass star NLTT 51469, which we reveal to be a close binary itself, separated by 0{^''.}64 ± 0{^''.}01 (˜30 au). We find the proper motion of SDSS

Aims: We determine the radii and masses of 293 nearby, bright M dwarfs of the CARMENES survey. This is the first time that such a large and homogeneous high-resolution (R > 80 000) spectroscopic survey has been used to derive these fundamental stellar parameters. Methods: We derived the radii using Stefan-Boltzmann's law. We obtained the required

We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V = 9) K1 dwarf observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 3 and 4. We combine the TESS photometry with archival High Accuracy Radial velocity Planet Searcher spectra to confirm the planetary

In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey. Qatar-8b is a hot Saturn, with M P = 0.37 M J and R P = 1.3 R J, orbiting a solar-like star every P orb = 3.7 days. Qatar-9b is a hot Jupiter with a mass of M P = 1.2 M J and a radius of R P = 1 R J, in an orbit of P orb = 1.5 days around a low mass, M ⋆ = 0.7 M

We report Spitzer Space Telescope observations during predicted transits of the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone planet we will ever discover, any potential transit of Proxima b would place strong constraints on its radius, bulk density, and atmosphere. Subsequent transmission spectroscopy and secondary