We have obtained deep CCD R and I mosaic imaging of 578 arcmin^2^ within 1°.5 of the Pleiades' center - reaching a completeness magnitude I = 19.5 - with the aim of finding free-floating brown dwarfs. Teide 1, the best bona fide brown dwarf discovered so far in the cluster (Rebolo, Zapatero Osorio & Martin, 1995Natur.377..129R), arose as a result

We present a model for the evolution of the light-nuclide abundances in the Galaxy, aimed especially at interpreting the observed beryllium and boron abundances as a function of that of iron. We present two models, one for the Galactic halo and the other for the Galactic disk. The main characteristics of the halo model are (1) the relatively rapid

We present observations taken with the Advanced Stokes Polarimeter (ASP) in active-region plages and study the frequency distribution of the magnetic field strength (B), inclination with respect to vertical ( gamma ), azimuthal orientation ( chi ), and filling factor (f). The most common values at disk center are B = 1400 G, gamma 10 deg, no

Planetary Nebulae (PNe) are highly representative of the last stages of intermediate mass stellar evolution. However, there are still many unresolved questions concerning their evolutionary scheme. Mass loss processes during the Asymptotic Giant Branch (AGB) are not fully understood. Binarity, rotation and magnetic fields may play an important role

Erratum to Astron. Astrophys. Suppl. Ser. 117 (1996) 227-254.

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