Related papers: Common Envelope Evolution on the Asymptotic Giant …
During the common envelope binary interaction, the expanding layers of the gaseous common envelope recombine and the resulting recombination energy has been suggested as a contributing factor to the ejection of the envelope. In this paper…
In this paper we investigate the level of agreement between observations and "new" Asymptotic Giant Branch (AGB) models, as produced by updating the physical inputs adopted in previous stellar computations. One finds that the new physics…
A significant fraction of planetary nebulae (PNe) and proto-planetary nebulae (PPNe) exhibit aspherical, axisymmetric structures, many of which are highly collimated. The origin of these structures is not entirely understood, however recent…
Post-common-envelope binaries (PCEBs) containing a white dwarf (WD) and a main-sequence (MS) star can constrain the physics of common envelope evolution and calibrate binary evolution models. Most PCEBs studied to date have short orbital…
We present preliminary results from Smooth Particle Hydrodynamics (SPH) simulations of common envelope evolution. We qualitatively compare the interaction between a 0.9M red giant with two different companion masses: a 0.05M brown dwarf and…
Born-again planetary nebulae (PNe) are extremely rare cases in the evolution of solar-like stars. It is commonly accepted that their central stars (CSPN) experienced a very late thermal pulse (VLTP), ejecting H-deficient material inside the…
Post-asymptotic giant branch (post-AGB) stars with discs are all binaries. Many of these binaries have orbital periods between 100 and 1000 days so cannot have avoided mass transfer between the AGB star and its companion, likely through a…
Although most white dwarf stars have hydrogen-dominated atmospheres, a significant fraction have atmospheres in which hydrogen is spectroscopically absent, with the fraction of hydrogen-free atmospheres varying with effective temperature.…
We conduct three-dimensional hydrodynamic simulations of the common envelope binary interaction and show that if the companion were to launch jets while interacting with the giant primary star's envelope, the jets would remove a substantial…
I suggest a spiral-in process by which a stellar companion graze the envelope of a giant star while both the orbital separation and the giant radius shrink simultaneously, and a close binary system is formed. The binary system might be…
The presence of a close, low-mass companion is thought to play a substantial and perhaps necessary role in shaping post-Asymptotic Giant Branch and Planetary Nebula outflows. During post-main-sequence evolution, radial expansion of the…
In this first in a series of papers related to long-period post-common-envelope (CE) binaries, we investigated whether extra energy is required or not to explain the currently known post-CE binaries with sufficiently long orbital periods…
The late stellar evolutionary phases of low and intermediate-mass stars are strongly constrained by their mass-loss rates. The wind surrounding cool evolved stars frequently shows non-spherical features, thought to be due to an unseen…
Context. The transition from the spherically symmetric envelopes around asymptotic giant branch (AGB) stars to the asymmetric morphologies observed in planetary nebulae is still not well understood, and the shaping mechanisms are a subject…
We find that the convective motion in the envelopes of red supergiant (RSG) stars supplies a non-negligible stochastic angular momentum to the mass that a secondary star accretes in a common envelope evolution (CEE), such that jets that the…
About ten percent of Sun-like ($1$-$2 M_\odot$) stars will engulf a $1$-$10 M_{\rm J}$ planet as they expand during the red giant branch (RGB) or asymptotic giant branch (AGB) phase of their evolution. Once engulfed, these planets…
I study some aspects of common envelope evolution, where a compact star enters the envelope of a giant star. I show that in some binary systems under a narrow range of parameters, a substantial fraction of the giant stellar envelope is lost…
Asymptotic Giant Branch (AGB) stars generally have spherically symmetric envelopes, whereas most post-AGB stars and Planetary Nebulae (PNe) show axisymmetric circumstellar envelopes. While various mechanisms for axisymmetric circumstellar…
We trace the evolution of central galaxies in three ~10^13 M_sun galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. The evolution in the group potential leads, at z=0, to central galaxies that are…
The evolution of central stars of planetary nebulae can proceed in several distinct ways, either leading to H-deficiency or to H-normal surface composition. Several new simulations of the evolution channels that lead to H-deficiency are now…