Related papers: Mass Transfer and Accretion in the Eccentric Neutr…
Circinus X-1 is a neutron-star-accreting X-ray binary in a wide (P$_{\rm orb}$ = 16.6 d), eccentric orbit. After two years of relatively low X-ray luminosity, in May 2010 Circinus X-1 went into outburst, reaching 0.4 Crab flux. This…
We study the evolution of a low mass x-ray binary coupling a binary stellar evolution code with a general relativistic code that describes the behavior of the neutron star. We assume the neutron star to be low--magnetized (B~10^8 G). In the…
Context. Ultracompact X-ray binaries (UCXBs) typically consist of a white dwarf donor and a neutron star or black hole accretor. The evolution of UCXBs and very low mass ratio binaries in general is poorly understood. Aims. We investigate…
Most studies of mass transfer in binary systems assume circular orbits at the onset of Roche lobe overflow. However, there are theoretical and observational indications that mass transfer could occur in eccentric orbits. In particular,…
We present the results of a systematic study of the evolution of low- and intermediate-mass X-ray binaries (LMXBs and IMXBs). Using a standard Henyey-type stellar-evolution code and a standard model for binary interactions, we have…
We present the first calculations of mass transfer via RLOF for a binary system with a significant eccentricity using our new binary stellar evolution code. The study focuses on a 1.50+1.40 Msun main sequence binary with an eccentricity of…
Circinus X-1 (Cir X-1) is a neutron star binary with an elliptical orbit of 16.6~days. The source is unique for its extreme youth, providing a key to understanding early binary evolution. However, its X-ray variability is too complex to…
The source 2A 1822-371 is an eclipsing low-mass X-ray binary (LMXB) consisting of a neutron star (NS) and a $\sim0.5~M_{\odot}$ donor star in an orbit of 5.57 hr. Based on timing of the eclipse arrival times, this source was found to be…
Accretion conditions and morphologies of X-ray transients containing neutron stars are still poorly understood. Circinus X-1 is an enigmatic case where we observe X-ray flux changes covering four orders of magnitude. We observed Circinus…
The X-ray transient XTE J1701-462 was the first source observed to evolve through all known subclasses of low-magnetic-field neutron star low-mass X-ray binaries (NS-LMXBs), as a result of large changes in its mass accretion rate. To…
We investigate Roche lobe overflow mass transfer (MT) in eccentric binary systems between stars and compact objects (COs), modeling the coupled evolution of both the star and the orbit due to eccentric MT (eMT) in a self-consistent…
We give a global analysis of mass transfer variations in low-mass X-ray binaries and cataclysmic variables whose evolution is driven by the nuclear expansion of the secondary star. We show that limit cycles caused by irradiation of the…
We study the spin evolution of X-ray neutron stars in binary systems, which are being spun up by mass transfer from accretion disks. Our investigation reveals that a quark phase transition resulting from the changing central density induced…
We present the results of simultaneous X-ray and radio observations of the peculiar Z-type neutron star X-ray binary Cir X-1, observed with the Rossi X-ray timing explorer satellite and the Australia Telescope Compact Array in 2000 October…
Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low energy…
Chandra observations of elliptical galaxies have revealed large numbers of Low Mass X-ray Binaries (LMXBs) accreting at rates above 10^-9 solar masses per year. One scenario which generates this transfer rate from an old stellar population…
We investigate the secular evolution of the orbital semi-major axis and eccentricity due to mass transfer in eccentric binaries, allowing for both mass and angular momentum loss from the system. Adopting a delta function mass transfer rate…
We have performed detailed numerical calculations of the non-conservative evolution of close binary systems with low-mass (1.0-2.0 M_sun) donor stars and a 1.3 M_sun accreting neutron star. Rather than using analytical expressions for…
Information about the last stages of a binary neutron star inspiral and the final merger can be extracted from quasi-equilibrium configurations and dynamical evolutions. In this article, we construct quasi-equilibrium configurations for…
X-rays trace accretion onto compact objects in binaries with low mass companions at rates ranging up to near Eddington. Accretion at high rates onto neutron stars goes through cycles with time-scales of days to months. At lower average…