Related papers: Critically rotating stars in binaries - an unsolve…
In some semi-detached binary systems, the donor star may transfer mass to the companion at a very high rate. We propose that, at sufficiently high mass-transfer rates such that the accretion disk around the companion becomes geometrically…
Despite numerous efforts to better understand binary star evolution, some aspects of it remain poorly constrained. In particular, the evolution of eccentric binaries has remained elusive mainly because the Roche lobe formalism derived for…
In order to predict the spins of stellar remnants we need to understand the evolution of the internal rotation of stars, and to identify at which stage the rotation of the contracting cores of evolved stars decouples from their expanding…
Motions of stars in close binary systems with a conservative mass exchange are examined. It is shown that Paczynski-Huang model widely used now for obtaining the semi-major axis variation of a relative stars orbit is incorrect, because it…
After the companion dynamically plunges through the primary's envelope, the two cores remain surrounded by a common envelope and the decrease of the orbital period $P_\text{orb}$ stalls. The subsequent evolution has never been…
State-of-the-art surveys reveal that most massive stars in the universe evolve in close binaries. Massive stars in such systems are expected to develop aspherical envelopes due to tidal interactions and/or rotational effects. Recently, it…
The LIGO and Virgo gravitational-wave detectors have uncovered binary black hole systems with definitively nonzero spins, as well as systems with significant spin residing in the more massive black hole of the pair. We investigate the…
We study the accretion efficiency of neutron stars in long-period binaries, i.e. with periods longer than about 200d, which accrete from a giant companion. Using alpha-disc models and taking into account the effect of irradiation of the…
It has been consensus that star-disk systems accrete most of their mass and angular momentum during the collapse of a prestellar core, such that the rotational direction of a system is equivalent to the net rotation of the core. Recent…
Age estimation techniques such as gyrochronology and magnetochronology can't be applied to stars that exchanged angular momentum with their close environment. This is especially true for massive close-in planetary companion (with a periods…
The formation of close massive black-hole binaries is a challenge for binary evolutionary models, especially the intriguing system M33 X-7 which harbours one of the most massive stellar-mass black holes (16 solar masses) orbiting a 70 solar…
Circumbinary discs are generally thought to take up angular momentum and energy from the binary orbit over time through gravitational torques mediated by orbital resonances. This process leads to the shrinkage of the binary orbit over time,…
Observations indicate that members of close stellar binaries often have mass ratios close to unity, while longer-period systems exhibit a more uniform mass-ratio distribution. This paper provides a theoretical explanation for this finding…
Precise astrometric measurement with Gaia satellite resulted in the discovery of tens of wide binary systems consisting of a Sun-like star and an invisible component. The latter can be a white dwarf, a neutron star, or a black hole. In this…
The effects of rapid rotation on stellar evolution can be profound. We are now beginning to gather enough data to allow a realistic comparison between different physical models. Two key tests for any theory of stellar rotation are first…
We outline a mechanism that explains the observed lack of circumbinary planets (CBPs) via coupled stellar-tidal evolution of isolated binary stars. Tidal forces between low-mass, short-period binary stars on the pre-main sequence slow the…
There is a remarkable correlation between the spin periods of the accreting neutron stars in Be/X-ray binaries (BeXBs) and their orbital periods . Recently Knigge et al. (2011) showed that the distribution of the spin periods contains two…
A neutron star in binary orbit with a low-mass non-degenerate companion becomes a source of x-rays with millisecond variability when mass accretion spins it up. Centrifugally driven changes in density profile may initiate a phase transition…
Close-orbit binaries consisting of two compact objects are a center of attention because of the detection of gravitational-radiation-induced mergers. The creation of close, compact-object binaries involves physical processes that are not…
We study the angular momentum evolution of binaries containing two white dwarfs which merge and become cool helium-rich supergiants. Our object is to compare predicted rotation velocities with observations of highly evolved stars believed…