Dependence of phenomenological properties of Cepheids on the heavy element abundance is studied. It is found that the amplitude of the pulsation depends on the metallicity of the stellar atmosphere.

A new stellar library developed for stellar population synthesis modelling is presented. The library consists of 985 stars spanning a large range in atmospheric parameters. The spectra were obtained at the 2.5-m Isaac Newton Telescope and cover the range λλ 3525-7500 Å at 2.3 Å (full width at half-maximum) spectral resolution. The spectral

We derive discrete and continuous class of mathematical models that describe a progressive collapse in a fictional one-dimensional structure, where we consider plastic and elastic types of collisions. We examine static (collapse initiation lines, derived from the ultimate yield strength of the structural steel) and dynamic (duration of collapse

On 2002 we started an observational campaign devoted to the study of the surface composition of Jupiter Trojans. In particular we focused on the study of members of dynamical families: we obtained visible spectra of 80 objects belonging to 10 different families and for 24 of them we obtained also near-infrared spectra. All the investigated bodies

The narrow-band optical images in several of the most important atomic lines and neighbouring continuum were secured at Las Campanas Observatory (LCO) in 1994 March 17-22, using the 40-in. telescope (LCO-40) and the TEK1 1024x1024 pixel detector. The narrow-band filters are centred in the following emission lines: H{beta}, [OIII] 5007{AA}, Hα, [NII

Aims.In order to show the importance of high spatial resolution observations of extra-galactic sources when compared to observations obtained with larger apertures such as ISO, we present N-band spectra (8-13 μm) of some locations in three starburst galaxies. In particular, we show the two galactic nuclei of the spiral galaxy NGC 3256, the compact