We study the modification of the classical criterion for the linear onset and growing rate of the Kelvin-Helmholtz Instability (KHI) and the Rayleigh-Taylor instability (RTI) in a partially ionised plasma in the two-fluid description. The plasma is composed of a neutral fluid and an electron-ion fluid, coupled by means of particle collisions. The

We performed an uniform spectroscopic analysis of 1111 FGK dwarfs observed as part of the HARPS GTO planet search program. We applied a purely chemical approach, based on [α/Fe] ratio, to distinguish the various stellar components in the Galaxy. Apart from the well known Galactic thick and thin disks, we separated an -enhanced stellar family at

In a previous work, we reported on the discovery of supersonic magnetic upflows on granular cells in data from the SUNRISE/IMaX instrument. In the present work, we investigate the physical origin of these events employing data from the same instrument but with higher spectral sampling. By means of the inversion of Stokes profiles we are able to

M 22 is an anomalous globular cluster that hosts two groups of stars with different metallicity and s-element abundance. The star-to-star light-element variations in both groups, with the presence of individual Na-O and C-N anticorrelations, demonstrates that this Milky Way satellite has experienced a complex star formation history. We have

Given the very close proximity of their habitable zones, brown dwarfs (BDs) represent high-value targets in the search for nearby transiting habitable planets that may be suitable for follow-up occultation spectroscopy. In this paper, we develop search strategies to find habitable planets transiting BDs depending on their maximum habitable orbital

Massive stars are fundamental drivers of the Universe because of their injection of energy, momentum, and nuclear-processed material in every stage of their life and death. Their feedback depends on their formation, winds and evolution, and these in turn depend on chemical composition. The GTC-OSIRIS combination is an excellent machine for