Aims:We calculate the bounds on the variation in the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We used these bounds and other bounds from the late universe to test the Bekenstein model. Methods: We modified the Kawano code, CAMB, and CosmoMC to include the possible variation in

Aims:We aim to provide the atmospheric parameters and rotational velocities for a large sample of O- and early B-type stars, analysed in a homogeneous and consistent manner, for use in constraining theoretical models. Methods: Atmospheric parameters, stellar masses, and rotational velocities have been estimated for approximately 250 early B-type

Context: The heating process that balances the solar chromospheric energy losses has not yet been determined. Conflicting views exist on the source of the energy and the influence of photospheric magnetic fields on chromospheric heating. Aims: We analyze a 1-h time series of cospatial Ca II H intensity spectra and photospheric polarimetric spectra

Observations of transverse coronal loop oscillations very often show the excitation and damping of oscillations in groups of coronal loops rather than in individual and isolated structures. We present results on the oscillatory properties (periods, damping rates, and spatial distribution of perturbations) for resonantly damped oscillations in a

We present new results on the nature of the Herbig-Haro-like object 73 (HHL 73, also known as [G84b] 11) based on narrow-band CCD Hα and [SII] images of the HHL 73 field, and integral field spectroscopy (IFS) and radio continuum observations at 3.6 cm covering the emission of the HHL 73 object. The CCD images allow us to resolve the HHL 73 comet

We have computed the K-correction for emission lines formed on the irradiated face of the companion stars in X-ray binaries. Our results, combined with the detection of high excitation emission lines arising from the donor star can provide the first mass determinations for either neutron stars or black holes in active Low Mass X-ray Binaries (LMXBs