Related papers: An Interacting Binary System Powers Precessing Out…
The common envelope (CE) interaction describes the swallowing of a nearby companion by a growing, evolving star. CEs that take place during the asymptotic giant branch phase of the primary and may lead to the formation of a planetary nebula…
Abundance anomalies observed in globular cluster stars indicate pollution with material processed by hydrogen burning. Two main sources have been suggested: asymptotic giant branch stars and massive stars rotating near the break-up limit.…
Accretion discs are common in binary systems, and they are often found to be misaligned with respect to the binary orbit. The gravitational torque from a companion induces nodal precession in misaligned disc orbits. We calculate whether…
Binary formation is an important aspect of star formation. One possible route for close-in binary formation is disk fragmentation$^{[1,2,3]}$. Recent observations show small scale asymmetries (<300 au) around young protostars$^{[2,4]}$,…
This chapter reviews the dynamical processes in young stellar clusters. The accretion of gas by individual stars affects the dynamics of the cluster, and the masses of the stars. Dynamical mass segregation cannot explain the degree of mass…
Planetary Nebulae are the ionised ejected envelopes surrounding the remnant cores of dying stars. Theory predicts that main-sequence stars with one to about eight times the mass of our sun may eventually form planetary nebulae. Until now no…
Why 80% of planetary nebulae are not spherical is not yet understood. The Binary Hypothesis states that a companion to the progenitor of the central star of a planetary nebula is required to shape the nebula and even for a planetary nebula…
Stars are mostly found in binary and multiple systems, as at least 50% of all solar-like stars have companions - a fraction that goes up to 100% for the most massive stars. Moreover, a large fraction of them will interact in some way or…
The morphologies of planetary nebula have long been believed to be due to wind shaping processes in which a fast wind from the central star impacts a previously ejected envelope. Asymmetries assumed to exist in the slow wind envelope lead…
In this review I present the binary model for the shaping of planetary nebulae (PNe) as I view it, in the context of historical evolution of other models for the shaping of PNe over more than 30 years. In describing the binary model, I…
One of the most poorly understood stellar evolutionary paths is that of binary systems undergoing common-envelope evolution, when the envelope of a giant star engulfs the orbit of a companion. Although this interaction leads to a great…
Binaries occur in many astrophysical systems, from young protostellar binaries in star forming regions to supermassive black hole binaries in galaxy centers. In many cases, a circumbinary disk of gas forms around the binary with an orbit…
Planet formation is often considered in the context of one circumstellar disk around one star. Yet stellar binary systems are ubiquitous, and thus a substantial fraction of all potential planets must form and evolve in more complex,…
Counterrotating stars in disk galaxies are a puzzling dynamical feature whose origin has been ascribed to either satellite accretion events or to disk instabilities triggered by deviations from axisymmetry. We use a cosmological simulation…
In this paper, we have reviewed the present status of the theory of equilibrium configurations of compact binary star systems in Newtonian gravity. Evolutionary processes of compact binary star systems due to gravitational wave emission can…
I study a triple star common envelope evolution (CEE) of a tight binary system that is spiraling-in inside a giant envelope and launches jets that spin-up the envelope with an angular momentum component perpendicular to the orbital angular…
X-ray binaries are binary star systems in which a compact object (a neutron star or a black hole) and a relatively normal star orbit a common centre of mass. Since the discovery of X-ray binaries with the first X-ray telescopes in the…
Binary stars commonly pass through phases of direct interaction which result in the rapid loss of mass, energy, and angular momentum. Though crucial to understanding the fates of these systems, including their potential as gravitational…
Jet systems with two unequal components interact with their parent accretion disks through the asymmetric removal of linear momentum from the star-disk system. We show that as a result of this interaction, the disk's state of least energy…
Asteroseismology has become an indispensable method for measuring stellar ages and radii, while binary systems remain the most prevalent tool for determining stellar masses. The synergy of the two, namely pulsating stars in binary systems,…