Massive stars can significantly modify the surrounding medium during their lifetime. When the stars explode as supernovae, the resulting shock wave expands within this modified medium and not within the interstellar medium. We explore the evolution of the medium around massive stars, and the expansion of the shock wave within this medium. We then apply these results to understanding the expansi...

Three-body effects greatly complicate stellar evolution. We model the effects of encounters of binaries with single stars, based on parameters chosen from conditions prevalent in the cores of globular clusters. For our three-body encounters, we start with a population of primordial binaries, and choose incoming stars from the evolving single star populations of paper I. In addition, we study th...

We model the dynamical evolution of star forming regions with a wide range of initial properties. We follow the evolution of the regions’ substructure using theQ–parameter, we search for dynamical mass segregation using the ΛMSR technique, and we also quantify the evolution of local density around stars as a function of mass using the ΣLDR method. The amount of dynamical mass segregation measur...

The implications of hyperon pairing for the thermal evolution of neutron stars containing hyperons are investigated. The outcome of cooling simulations are compared for neutron star models composed only of nucleons and leptons, models including hyperons, and models including pairing of hyperons. We show that lambda and neutron pairing suppresses all possible fast neutrino emission processes in ...

Big Bang nucleosynthesis produces only light elements and the very first generation stars are thus formed from metal-free clouds. They start the production of heavy elements during their life, and enrich the interstellar medium through their explosive death. Stellar evolution models show that the treatment of rotation has important effects on the evolution of those metal-free stars: for example...

I present the results of radiation-driven mass-loss predictions for hot stars of all mass. Mass loss is an important aspect for the evolution of massive stars, the rotational properties of the progenitors of gamma-ray bursts, and is essential in assessing whether the most massive stars explode as pair-instability supernovae, or avoid them due to mass loss. As a result, the rate of mass loss is ...

Context. With growing evidence for the existence of very massive stars at subsolar metallicity, there is an increased need for corresponding stellar evolution models. Aims. We present a dense model grid with a tailored input chemical composition appropriate for the Large Magellanic Cloud (LMC). Methods. We use a one-dimensional hydrodynamic stellar evolution code, which accounts for rotation, t...

We have measured the Li abundance of 18 stars with and K, [2 [ [Fe/H][ [1 6000 [ Teff [ 6400 a parameter range that was poorly represented in previous studies. We examine the Galactic chemical evolution (GCE) of this element, combining these data with previous samples of turno† stars over the full range of halo metallicities. We Ðnd that A(Li) increases from a level of D2.10 at [Fe/H]\ [3.5 to ...

Context. The Hertzsprung-Russell diagram is a key diagnostic diagram for stellar structure and evolution, which is now in use for more than 100 years. Aims. We introduce a new diagram which is based on the gravity-effective temperature diagram, but has various advantages. Methods. Our spectroscopic Hertzsprung-Russell (sHR) diagram shows the inverse of the flux-mean gravity versus the effective...

Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting Neptune-mass object, presents a difficult case because it is an M dwarf. Stellar models in this mass regime are not as reliable as for higher mass stars, and te...