Related papers: The Formation of Hydrogen Deficient Stars through …
We simulate the dynamical, chemical, and spectro-photometric evolution of dwarf and normal elliptical galaxies embedded in a dark matter halo, using a three-dimensional N-body/SPH simulation code. For the forming dwarf elliptical galaxies,…
We have examined consequences of strong tidal encounters between a neutron star and a normal star using SPH as a possible formation mechanism of isolated recycled pulsars in globular clusters. We have made a number of SPH simulations for…
Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from…
The common envelope (CE) interaction between an expanding giant star and a compact companion typically leads to a rapid orbital decay, ending in either a merger or the formation of a close binary. However, the existence of post-red giant…
The formation scenarios for single low-mass (M < 0.45 Msol) white dwarfs include enhanced mass loss from a metal-rich progenitor star or a common envelope phase of a solar-like star with a close-in massive planet or a brown dwarf. Both…
White dwarfs represent the endpoint of stellar evolution for stars with initial masses between approximately 0.07 msun and 8-10 msun, where msun is the mass of the Sun (more massive stars end their life as either black holes or neutron…
We present first results from three-dimensional hydrodynamic simulations of the high redshift formation of dwarf galaxies. The simulations use an Eulerian adaptive mesh refinement technique to follow the non-equilibrium chemistry of…
As a result of competing physical mechanisms, the atmospheric composition of white dwarfs changes throughout their evolution, a process known as spectral evolution. Because of the ambiguity of their atmospheric compositions and the…
We present hydrodynamic simulations of the common envelope binary interaction between a giant star and a compact companion carried out with the adaptive mesh refinement code ENZO and the smooth particle hydrodynamics code PHANTOM. These…
After the discovery of a substellar companion to the hot subdwarf HD 149382, we have started a radial velocity search for similar objects around other bright sdB stars using the Anglo-Australian Telescope. Our aim is to test the hypothesis…
The early phase of the hydrodynamic evolution following collision of two stars is analyzed. Two strong shocks propagate at a constant velocity (which is a small fraction of the velocity of the approaching stars) from the contact surface…
We review the current status of compact object simulations that are based on the Smooth Particle Hydrodynamics (SPH) method. The first main part of this review is dedicated to SPH as a numerical method. We begin by discussing relevant…
We propose a common envelope evolution (CEE) scenario where a red giant branch (RGB) star engulfs a planet during its core helium flash to explain the puzzling system WD 1856+534 where a planet orbits a white dwarf (WD) of mass 0.52Mo with…
An interaction between a star-disc system and another star will perturb the disc, possibly resulting in a significant modification of the disc structure and its properties. It is still unclear if such an encounter can trigger fragmentation…
Hot subdwarf stars with masses above $0.8 M_\odot$ ascend the helium giant branch after the end of core helium burning, before entering the white dwarf cooling track or exploding as type Ib/c supernovae. Such massive helium stars are…
It has long been speculated that jet feedback from accretion onto the companion during a common envelope (CE) event could affect the orbital evolution and envelope unbinding process, but this conjecture has heretofore remained largely…
It is predicted that orbital decay by gravitational-wave radiation and tidal interaction will cause some close-binary stars to merge within a Hubble time. The merger of a helium-core white dwarf with a main-sequence star can produce a red…
Long-period binary systems containing a B-type hot subdwarf (sdB) and a main-sequence companion are thought to originate from binary interactions involving stable mass transfer from the red giant, the progenitor of the sdB, to the MS…
We present a new numerical study of the equilibrium and stability properties of close binary systems using the smoothed-particle hydrodynamics (SPH) technique. We adopt a simple polytropic equation of state $p=K\rho^\gam$ with $\gam=5/3$…
Binaries that contain a hot subdwarf (sdB) star and a main sequence companion may have interacted in the past. This binary population has historically helped determine our understanding of binary stellar evolution. We have computed a grid…