Stellar activity is ubiquitously encountered in M dwarfs and often characterised by the Hα line. In the most active M dwarfs, Hα is found in emission, sometimes with a complex line profile. Previous studies have reported extended wings and asymmetries in the Hα line during flares. We used a total of 473 high-resolution spectra of 28 active M dwarfs

Context. The new CARMENES instrument comprises two high-resolution and high-stability spectrographs that are used to search for habitable planets around M dwarfs in the visible and near-infrared regime via the Doppler technique. Aims: Characterising our target sample is important for constraining the physical properties of any planetary systems

Here we present the Adaptive Optics Lucky Imager (AOLI), a state-of-the-art instrument which makes use of two well proved techniques, Lucky Imaging (LI) and Adaptive Optics (AO), to deliver diffraction limited imaging at visible wavelengths, 20 mas, from ground-based telescopes. Thanks to its revolutionary TP3-WFS, AOLI shall have the capability of

A new prime focus corrector for the WEAVE project for the William Herschel Telescope is being produced. The corrector consists of six lens elements, the largest being 1.1 m in diameter. It also incorporates an Atmospheric Dispersion Corrector. Testing procedures for the WEAVE prime focus corrector lens elements are described here. Critical issues

Eine der rätselhaftesten astronomischen Entdeckungen der letzten Jahre waren die seltsamen Helligkeitsschwankungen des Sterns KIC 8462852 in den Daten des Weltraumteleskops Kepler. Neue Beobachtungen zeigen, dass diese Variationen von der Absorption durch feinen Staub herrühren, der sich vermutlich von Planetesimalen nahe dem Stern löst.

We present here SPECULOOS, a new exoplanet transit search based on a network of 1m-class robotic telescopes targeting the 1200 ultracool (spectral type M7 and later) dwarfs bright enough in the infrared (K-mag