Related papers: Simulating a binary system that experiences the gr…
I propose that some irregular `messy' planetary nebulae owe their morphologies to triple-stellar evolution where tight binary systems evolve inside and/or on the outskirts the envelope of asymptotic giant branch (AGB) stars. In some cases…
Triple stellar systems allow us to study stellar processes that cannot be attained in binary stars. The evolutionary phases in which the stellar members undergo mass exchanges can alter the hierarchical layout of these systems. Yet, the…
Massive stars commonly form binaries that can evolve into compact systems via common envelope evolution (CEE), a critical but poorly understood phase -- especially when the companion is a neutron star. Understanding the drag force exerted…
I summarize recent analytical and numerical studies of the common envelope (CE) process and suggest to replace the commonly used alpha-prescription for the CE ejection by a prescription based on final migration and jets launched by the…
Binary neutron stars have been observed as millisecond pulsars, gravitational-wave sources, and as the progenitors of short gamma-ray bursts and kilonovae. Massive stellar binaries that evolve into merging double neutron stars are believed…
Binary stars are common. While only those with small separations may exchange gas with one another, even the widest binaries interact with their gaseous surroundings. Drag forces and accretion rates dictate how these systems are transformed…
We simulate the formation of bipolar planetary nebulae (PNe) through very short impulsive mass ejection events from binary systems, where the asymptotic giant branch (AGB) star ejects a mass shell that is accelerated by jets launched from a…
We study the bending of jets in binary stellar systems. A compact companion accretes mass from the slow wind of the mass-losing primary star, forms an accretion disk, and blows two opposite jets. These fast jets are bent by the slow wind.…
Modeling the evolution of progenitors of gravitational-wave merger events in binary stars faces two major uncertainties: the common-envelope phase and supernova kicks. These two processes are critical for the final orbital configuration of…
Tight and compact binary systems, such as double neutron star binaries, are believed to undergo a common envelope evolution phase, resulting in strongly bound orbits. During this phase, the outer layers of the primary star are expelled,…
Common envelope (CE) is an important phase in the evolution of interacting evolved binary systems. The interaction of the binary components during the CE evolution (CEE) stage gives rise to orbital inspiral and the formation of a…
With a one-dimensional stellar evolution model, we find that massive main-sequence stars can accrete mass at very high mass accretion rates without expanding much if they lose a significant fraction of this mass from their outer layers…
Planets and other low-mass binary companions to stars face a variety of potential fates as their host stars move off the main sequence and grow to subgiants and giants. Stellar mass loss tends to make orbits expand, and tidal torques tend…
We analyze a 3D hydrodynamic simulation of common envelope evolution to understand how energy is transferred between various forms and whether theory and simulation are mutually consistent given the setup. Virtually all of the envelope…
Most of massive stars form in binary or higher-order systems in clumpy, sub-structured clusters. In the very first phases of their life, these stars are expected to interact with the surrounding environment, before being released to the…
In close binary star systems, common envelope evolution may occur after a previous phase of mass transfer. Some isolated formation channels for double neutron star binaries suggest that the donor of common envelope evolution was the…
Most globular clusters (GCs) show evidence for multiple stellar populations, suggesting the occurrence of several distinct star-formation episodes. The large fraction of second population (2P) stars observed requires a very large 2P gaseous…
Our improving understanding of the life cycle of planetary systems prompts investigations of the role of the Galactic environment before, during and after Asymptotic Giant Branch (AGB) stellar evolution. Here, we investigate the interplay…
After the detection of GRB 170817A, the first unambiguous off-axis gamma-ray burst (GRB), several studies tried to understand the structure of GRB jets. The initial jet structure (directly produced by the central engine) can be partially…
Asymmetric shapes and evidence for binary central stars suggest a common-envelope origin for many bipolar planetary nebulae. The bipolar components of the nebulae are observed to expand faster than the rest and the more slowly expanding…