Spectroscopic analyses of stellar chemical compositions are model-dependent, and shortcomings in the models often limit the accuracy of the final results. For...

Massive stars (at least eight times as massive as the Sun) possess strong stellar winds driven by radiation. With the advent of the so called MiMeS...

Gaia all-sky scanning and multi-epoch photometric and spectroscopic observations offer unprecedented opportunities to detect and characterise magnetic activity...

Unlike the giant planets in the solar system, "hot Jupiter" giant exoplanets are subject to intense stellar irradiation, which drives their atmospheres from...

The new generation of spectrometers designed for extreme precision radial velocities enable correspondingly precise stellar spectroscopy. It is now fruitful to...

The intrinsic magnetic fields of exoplanets influence the structure of their atmospheres and plasmaspheres and, consequently, the observational manifestations...

Activity of cool dwarf stars can reveal itself in the form of high-energy radiation (eg, enhanced X-ray coronal emission, flares) and particles (eg, winds...

The Institute for Astrophysics and Geophysics (IAG) in Göttingen operates a Fourier-Transform Spectrograph (FTS) that can be fed by either a 50cm siderostat or...

The James Webb Space Telescope has shown us that we cannot consider exoplanet atmospheres as globally uniform objects in chemical equilibrium. On the contrary...