We analyze data on pulsation amplitudes and phases for two β Cephei stars, δ Cet and ν Eri. Strömgren photometry and radial velocity measurements are used simultaneously to obtain constraints on mean parameters of the stars and identification of the excited modes. The inference about the radial mode order and mean star parameters is based on comparison of certain complex parameter, f , determin...

The nucleosynthesis in asymptotic giant branch stars (briefly: AGB)is a challenging and fascinating subject in the theory of stellar evolution and important for observations as well. This is because about of half the heavy elements beyond iron are synthesized during thermal pulsation phases of these stars. Furthermore, the understanding of the production of the heavy elements and some light ele...

We have investigated the effects of uniform rotation and a specific model for differential rotation on the pulsation frequencies of 10 M⊙ stellar models. Uniform rotation decreases the frequencies for all modes. Differential rotation does not appear to have a significant effect on the frequencies, except for the most extreme differentially rotating models. In all cases, the large and small sepa...

Although wet (oil injected) and dry (oil free) screw compressors are widely used in many applications, limited information is available regarding the pulsation, vibration, and noise problems associated with these types of compressors. This tutorial discusses such problems and includes case histories where field testing was performed, and provides design recommendations. Both wet and dry screw c...

We present a new oscillation code, GYRE, which solves the stellar pulsation equations (both adiabatic and non-adiabatic) using a novel Magnus Multiple Shooting numerical scheme devised to overcome certain weaknesses of the usual relaxation and shooting schemes appearing in the literature. The code is accurate (up to sixth-order in the number of grid points), robust, efficiently makes use of mul...

We present period-luminosity diagrams for nearby Miras and semiregulars, selecting stars with parallaxes better than 20 per cent and well-determined periods. Using K-band magnitudes, we find two well-defined P-L sequences, one corresponding to the standard Mira P-L relation and the second shifted to shorter periods by a factor of about 1.9. The second sequence only contains semiregular variable...

We present an analytical study of the effect of small convective cores on the oscillations of solar-like pulsators. Based on an asymptotic analysis of the wave equation near the center of the star, we derive an expression for the perturbations to the frequencies of radial modes generated by a convective core and discuss how these perturbations depend on the properties of the core. Moreover, we ...

The problem of relativistic stellar pulsations is studied in a somewhat ad hoc approximation that ignores all fluid motions. This Inverse Cowling Approximation (ICA) is motivated by two observations: 1) For highly damped (w-mode) oscillations the fluid plays very little role. 2) If the fluid motion is neglected the problem for polar oscillation modes becomes similar to that for axial modes. Usi...