The ultra-hot Jupiter (UHJ) TOI-2109b marks the lower edge of the equilibrium temperature gap between 3500 and 4500 K, an unexplored thermal regime that separates KELT-9b, the hottest planet yet discovered, from all other currently known gas giants. To study the thermochemical structure of TOI-2109b's atmosphere, we obtained high-resolution

Context. Evolved cool stars have three distinct evolutionary status: shell-hydrogen burning (RGB), core-helium and shell-hydrogen burning (RC), and double-shell burning (AGB). Asteroseismology can distinguish between the RC and the other status, but distinguishing RGB and AGB has been difficult seismically and spectroscopically. The precise

Analysing high-resolution solar atmospheric observations requires robust techniques to recover plasma flow features across different scales, especially in active regions. Current methodologies often fall short in capturing subgranular-scale flows, and there is limited research on the errors introduced by velocity estimation techniques and analysing

Context. Spicules are elongated, jet-like structures that populate the solar chromosphere and are rooted in the lower solar atmosphere. In recent years, high-resolution observations and advanced numerical simulations have provided insights into their properties, structures, and dynamics. However, the formation mechanism of spicules, particularly

We use numerical mass density profiles from the TNG50 simulation to study the impact of gravitational milli-lensing by dark matter subhaloes on the images of lensed quasars. Specifically, we study the formation of subimages and the probability of their detection. For high-concentration density profiles, the mass determines the amplitude of the

In the gravitational lens SDSS J1004+4112, a background quasar is lensed by a galaxy cluster, hence the light from the quasar images travels mainly through the intracluster medium. Observations in the continuum emission and the broad line region detected variability due to microlensing in the multiple images of the quasar. In this work, we use the