Related papers: Diffusion and pulsations in slowly rotating B star…
The Galactic disk retains a vast amount of information about how it came to be, and how it evolved over cosmic time. However, we know very little about the secular processes associated with disk evolution. One major uncertainty is the…
We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover…
The angular momentum (AM) evolution of stellar interiors, along with the resulting rotation rates of stellar remnants, remains poorly understood. Asteroseismic measurements of red giant stars reveal that their cores rotate much faster than…
In the presence of rotation-induced mixing, element diffusion still occurs in stellar radiative zones, although at a slower rate than in the case of a complete stability of the stellar gas. As a consequence, helium settling leads to…
The impact of new stellar evolution models with rotation on the predictions of population synthesis models is discussed. Massive rotating stars have larger convective cores than their non-rotating counterparts, and their outer layers are…
The mass of the outer convective zone in FGK main sequence stars decreases dramatically with stellar mass. Therefore, any contamination of a star's atmosphere by accreted planetary material should affect hotter stars much more than cool…
A low mass star usually experiences stratification and abundance anomalies during its evolution. A 0.95 solar mass star with a metallicity Z = 0.004 is followed from the main-sequence to the Horizontal Branch (HB). On the main-sequence the…
The stability of retrograde mixed modes in rotating B-type stars is investigated. It is found that these modes are susceptible to kappa-mechanism excitation, due to the iron opacity bump at log T ~ 5.3. The findings are discussed in the…
The partial mixing of matter between the radiative envelope and the convective core in the early type B--star produces an additional increase of star luminosity during the main sequence evolution. The high quality data on stellar mass and…
The helium-atmosphere (DB) white dwarfs are commonly thought to be the descendants of the hotter PG 1159 stars, which initially have uniform He/C/O atmospheres. In this evolutionary scenario, diffusion builds a pure He surface layer which…
In this work we consider the effect that the appearance of pseudoscalar condensates in a neutron star can have on its cooling rate. We make no particular assumption on the origin and characteristics of these possible condensates and only…
The spin-down of Be stars due to angular momentum transport from star to disc has been considered. This has been prompted by empirical studies of observed optical and IR line profile studies indicating that the disc is rotating in a…
Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary…
We briefly review the main problems related to the computation of the evolution of intermediate-mass stars: the treatment of turbulent convection and the occurrence of blue loops during the core He-burning phase. It is shown that, in order…
Chemical composition is an important factor that affects stellar evolution. The element abundance on the stellar surface evolves along the lifetime of the star because of transport processes, including atomic diffusion. However, models of…
Thermal convection is one of the main mechanisms of heat transport and mixing in stars in general and also in the photospheric layers which emit the radiation that we observe with astronomical instruments. The present lecture notes first…
Stars consume hydrogen in their interiors but, generally speaking, their surfaces continue to contain some 70% hydrogen (by mass) throughout their lives. Nevertheless, many types of star can be found with hydrogen-deficient surfaces, in…
Neutron stars provide a fertile environment for exploring superfluidity under extreme conditions. It is not surprising that Cooper pairing occurs in dense matter since nucleon pairing is observed in nuclei as energy differences between…
The possibility of the phenomenon of Bose condensation having a part to play in the discussion of neutron stars has been around for some time. Here the sorts of temperatures and densities that might be involved are discussed. Also, an…
We present here the results of our research for B-type pulsators in low metallicity environments, searching for short-term periodic variability in a large sample of B and Be stars in the Magellanic Clouds (MC), for which the fundamental…