The determination of the brown dwarf binary fraction may contribute to the understanding of the substellar formation mechanisms. Unresolved brown dwarf binaries may be revealed through their peculiar spectra or the discrepancy between optical and near-infrared spectral-type classification. We obtained medium-resolution spectra of 22 brown dwarfs

Context. The potentially hazardous asteroid (PHA) (99942) Apophis is one of the most remarkable near-Earth asteroids (NEA) in terms of impact hazard. A good determination of its surface thermal inertia is very important in order to evaluate the Yarkovsky effect on its orbital evolution. Aims: We present thermal infrared observations obtained on

Star formation in galaxies over cosmic time may be driven by gas accretion from the cosmic web. Spectra of local extremely metal-poor galaxies (XMPs), obtained using the Gran Telescopio Canarias, show oxygen abundances that decrease by a factor of 5 to 10 in the main star-forming regions compared with the disks in 9 of 10 observed galaxies. The

Interstellar dust grain alignment gives rise to polarization from UV to mm wavelengths, allowing the study of the geometry and strength of the magnetic field. Over the last couple of decades observations and theory have led to the establishment of the Radiative Alignment Torque (RAT) mechanism as the leading candidate to explain the effect. With a

Asymptotic giant branch (AGB) stars are a main site of production of nuclei heavier than iron via the s process. In massive (>4 M⊙) AGB stars the operation of the 22Ne neutron source appears to be confirmed by observations of high Rb enhancements, while the lack of Tc in these stars rules out 13C as a main source of neutrons. The problem is that

While both exoplanets and stellar-mass companions have been found in extremely short-period orbits, there has been a paucity of brown dwarf (BD) companions orbiting Sun-like stars, a phenomenon known as the "Brown Dwarf Desert." However, more recent work has shown that this Desert might be limited in extent, only existing for small separation (a 5