Subgiants and early red giants are crucial for studying the first dredge-up, a key evolutionary phase in which the convective envelope deepens, mixing...

We have carried out a photometric and spectroscopic survey of bright high-amplitude δ Scuti (HADS) stars. The aim was to detect binarity and multiperiodicity...

Multi-epoch radial velocity measurements of stars can be used to identify stellar, substellar, and planetary-mass companions. Even a small number of observation...

Context. The extreme contrast ratios between stars and their planets at optical wavelengths make it challenging to isolate the light reflected by exoplanet...

Context. Stellar activity variability is one of the main obstacles to the detection of Earth-like planets using the radial velocity (RV) method. Aims. The aim...

A general framework for dealing with irradiation effects in the bolometric sense—specifically, reflection with heat absorption and the consequent redistribution...

We present an observational and numerical study of the borderline hyperbolic comet C/2021 O3 (PANSTARRS) performed during its recent passage through the inner...

1ES 1959+650 is a bright TeV high-frequency-peaked BL Lac object exhibiting interesting features like "orphan" TeV flares and broad emission in the high-energy...

We examine the capabilities of a fast and simple method to infer line-of-sight (LOS) velocities from observations of the photospheric Si I 10 827 Å line. This...