We overview the different classes of B-type pulsators and show from our ground-based data that current data sets are insufficient to derive the complete frequency spectrum. From line-profile studies, we find that many modes with small amplitudes are excited in some stars, of which extensive ground-based photometry has revealed only one frequency

A method based on Lucy's iterative algorithm is developed to invert the equation of stellar statistics for the Galactic bulge and is then applied to the K-band star counts from the Two-Micron Galactic Survey in a number of off-plane regions (10 deg>|b|>2 deg, |l|

OB associations and young open clusters constitute the most prolific nucleosynthesis sites in our Galaxy. The combined activity of stellar winds and core-collapse supernovae ejects significant amounts of freshly synthesised nuclei into the interstellar medium. Radioactive isotopes, such as 26Al or 60Fe, that have been co-produced in such events may

We quantify the energy radiated through all the collisionally excited lines in a photoionized nebula which is permeated by temperature fluctuations. We assume that these correspond to hot spots which are the results of an unknown heating process distinct from the photoelectric heating. We consider all the effects of using a higher mean temperature

By comparison of different parameters associated with a chaotic evolution, we discuss the relation between several populations of inner Solar System bodies. Tancredi (1998) found that the observed sample of Jupiter family comets (JFCs) and near-Earth asteroids (NEAs) have Lyapunov times (the inverse of Lyapunov characteristic exponents) grouped in

Not Available