Related papers: Element stratification in main sequence stars and …
The empirical laws of star formation suggest that galactic-scale gravity is involved, but they do not identify the actual triggering mechanisms for clusters in the final stages. Many other triggering processes satisfy the empirical laws…
Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt…
Turbulent mixing in the radiative regions of stars is usually either ignored or crudely accounted for in most stellar evolution models. However, there is growing theoretical and observational evidence that such mixing is present and can…
It has long been known that dissipation is a crucial ingredient in the superradiant amplification of wavepackets off rotating objects. We show that, once appropriate dissipation mechanisms are included, stars are also prone to superradiance…
Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant…
The process of convective settling is based on the assumption that a small fraction of the low-entropy downflows sink from the photosphere down to the bottom of the star's envelope convection zone retaining a substantial entropy contrast.…
There has been tremendous progress in observing oscillations in solar-type stars. In a few short years we have moved from ambiguous detections to firm measurements. We briefly review the recent results, most of which have come from…
Stars play a decisive role in our Universe, from its beginning throughout its complete evolution. For a thorough understanding of their properties, evolution, and physics of their outer envelopes, stellar spectra need to be analyzed by…
Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem…
Owing to the remarkable photometric precision of space observatories like Kepler, stellar and planetary systems beyond our own are now being characterized en masse for the first time. These characterizations are pivotal for endeavors such…
We investigate induced oscillations by the gravitational field of a fast stellar object, such as a neutron star or a black-hole in a near miss collision with another star. Non-adiabatic collision conditions may lead to large amplitude…
We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in…
The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the…
Rotation appears as a dominant effect in massive star evolution. It largely affects all the model outputs: inner structure, tracks, lifetimes, isochrones, surface compositions, blue to red supergiant ratios, etc. At lower metallicities, the…
Stars are not smooth. Their photosphere is covered by a granulation pattern associated with the heat transport by convection. The convection-related surface structures have different size, depth, and temporal variations with respect to the…
Parameter regions in which stars can become pulsationally unstable are found throughout the Hertzsprung-Russel diagram. Stars of high, intermediate, low and very low masses may cross various instability regions along their paths of…
Star formation is thought to be triggered by gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…
The helium-peculiar star a Cen exhibits line profile variations of elements such as iron, nitrogen and oxygen in addition to its well-known extreme helium variability. New high S/N, high-resolution spectra are used to perform a quantitative…
Accumulation of new data on stellar hierarchical systems and the progress in numerical simulations of their formation open the door to genetic classification of these systems, where properties of a certain group (family) of objects are…
Aims. Atomic diffusion, including the effect of radiative accelerations on individual elements, leads to important variations of the chemical composition inside the stars. The accumulation in specific layers of the elements, which are the…