Aims. Using the direct-imaging technique, we searched for low-mass companions around
the star AF Lep, which presents a significant proper-motion anomaly (PMa) signal obtained …

Observations of circumstellar environments that look for the direct signal of exoplanets and
the scattered light from disks have significant instrumental implications. In the past 15 years …

Direct detection and spectral characterization of extra-solar planets is one of the most
exciting but also one of the most challenging areas in modern astronomy. The challenge …

Benchmark brown dwarf companions with well-determined ages and model-independent
masses are powerful tools to test substellar evolutionary models and probe the formation of …

Context. In recent decades, direct imaging has confirmed the existence of substellar
companions (exoplanets or brown dwarfs) on wide orbits (> 10 au) around their host stars. In …

Context. Reference-star differential imaging (RDI) is a promising technique in high-contrast
imaging that is thought to be more sensitive to exoplanets and disks than angular differential …

Context. The planetary system discovered around the young A-type HR 8799 provides a
unique laboratory to: a) test planet formation theories; b) probe the diversity of system …

Much of the progress in astronomy has been driven by instrumental developments, from the
first telescopes to fiber fed spectrographs. In this review, we describe the field of …

The detection of a wide range of substructures such as rings, cavities, and spirals has
become a common outcome of high spatial resolution imaging of protoplanetary disks, both …

Context. HR 4796 A is surrounded by a debris disc, observed in scattered light as an
inclined ring with a high surface brightness. Past observations have raised several …