An introduction to the theory of no radial modes of oscillations is presented. Evidences of such pulsations can be found in numerous variable stars. We discuss here some new results obtained in stars varying with periods of the order or longer than the hour, namely β Cep stars, line profile variable stars and WR stars.
Vertex deviation in the galactic plane is not compatible with the
Oort-Lindbalad theory about galactic rotation (stationary system with cylindrical symmetry). However, like we show in this work, it can be obtained in a stellar system model that verifies the Chandrasekhar postulates in a non-stationary state, axial symmetry, non-cylindrical, and with an equatorial plane of symmetry.
A number of effects which can affect the low-mass IMF derived from the local luminosity function is studied. We consider an influence of unresolved binairies, variations in fine structure of mass-luminosity relation, BC-scale, chemical composition, and evolution of brown dwarfs. The mass-luminosity relation is found to be the main factor defining the IMF. As analysis shows, different theoretical relations calculated for Pop I composition result in different IMFs /from a power law, to a lognormal one/. The presence at faintest magnitudes /Mν > 20^m/ of a large number of brown dwarfs, slowly evolving with decreasing luminosity, leads to the depletion of the luminosity function for both lognormal and power IMFs.