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Quasi-spherical subsonic accretion onto slowly rotating magnetized NS is considered, when the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasi-static shell. The shell mediates the angular…

High Energy Astrophysical Phenomena · Physics 2013-10-24 N. I. Shakura , K. A. Postnov , A. Yu. Kochetkova , L. Hjalmarsdotter

The abundances of the chemical elements observed at the surface of metal-poor stars are not always representative of their initial values. During stellar evolution, various physical processes modify their internal composition. In this short…

Solar and Stellar Astrophysics · Physics 2011-08-26 Sylvie Vauclair

Nuclear reactions occurring deep in the crust of a transiently accreting neutron star efficiently maintain the core at a temperature >5e7 K. When accretion halts, the envelope relaxes to a thermal equilibrium set by the flux from the hot…

Astrophysics · Physics 2009-10-30 Edward F. Brown , Lars Bildsten , Robert E. Rutledge

Studies of element abundances in stars are of fundamental interest for their impact in a wide astrophysical context, from our understanding of galactic chemistry and its evolution, to their effect on models of stellar interiors, to the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Paola Testa

We outline the phenomenon of deep crustal heating in transiently accreting neutron stars. It is produced by nuclear transformations (mostly, by pycnonuclear reactions) in accreted matter while this matter sinks to densities rho > 10^{10}…

Astrophysics · Physics 2007-05-23 D. G. Yakovlev , K. P. Levenfish

Fusion of very neutron rich nuclei may be important to determine the composition and heating of the crust of accreting neutron stars. We present an exploratory study of the effect of the neutron-gas environment on the structure of nuclei…

Nuclear Theory · Physics 2015-09-01 A. S. Umar , V. E. Oberacker , C. J. Horowitz , P. -G. Reinhard , J. A. Maruhn

X-ray luminosities of accreting T Tauri stars are observed to be systematically lower than those of non-accretors. There is as yet no widely accepted physical explanation for this effect, though it has been suggested that accretion somehow…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Jeremy J. Drake , Barbara Ercolano , Ettore Flaccomio , Giusi Micela

Accretion from a disk onto a collapsed, relativistic star -- a neutron star or black hole -- is the mechanism widely believed to be responsible for the emission from compact X-ray binaries. Because of the extreme spatial resolution…

Astrophysics · Physics 2009-11-10 D. R. Ballantyne , T. E. Strohmayer

Type-I X-ray bursts on the surface of a neutron star are a unique probe to the accretion in X-ray binary systems. However, we know little about the feedback of the burst emission upon accretion. Hard X-ray shortages and enhancements of the…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Long Ji , Shu Zhang , YuPeng Chen , Shuang-Nan Zhang , Diego F. Torres , Peter Kretschmar , Erik Kuulkers , Jian Li , Zhi Chang

Some recent observations of the abundances of s-process, r-process, and alpha elements in metal-poor stars have led to a new scenario for their formation. According to this scenario, these stars were born in a globular cluster and accreted…

Astrophysics · Physics 2009-11-07 A. Thoul , A. Jorissen , S. Goriely , E. Jehin , P. Magain , A. Noels , G. Parmentier

The simulation of heavy element nucleosynthesis requires input from yet-to-be-measured nuclear properties. The uncertainty in the values of these off-stability nuclear properties propagates to uncertainties in the predictions of elemental…

High Energy Astrophysical Phenomena · Physics 2024-04-08 M. R. Mumpower , T. M. Sprouse , J. M. Miller , K. A. Lund , J. Cabrera Garcia , N. Vassh , G. C. McLaughlin , R. Surman

Massive-star binaries can undergo a phase where one of the two stars expands during its advanced evolutionary stage as a giant and envelops its companion, ejecting the hydrogen envelope and tightening its orbit. Such a common envelope phase…

A neutron star in a long-lived, low-mass binary can easily accrete enough matter to replace its entire crust. Previous authors noted that an accreted crust, being formed from the burning of accreted hydrogen and helium, allows a series of…

Astrophysics · Physics 2009-10-31 Edward F. Brown

Accretion of interstellar material by an isolated neutron star is discussed. The point I address here is the interaction between the accretion flow and the stellar magnetosphere. I show that the interchange instabilities of the…

Astrophysics · Physics 2008-11-26 N. R. Ikhsanov

The appearance and time variability of accreting millisecond X-ray pulsars (hereafter AMXPs, e.g. Wijnands & van der Klis 1998) depends strongly on the accretion rate, the effective viscosity and the effective magnetic diffusivity of the…

Astrophysics · Physics 2009-11-13 Marina M. Romanova , Akshay K. Kulkarni , Min Long , Richard V. E. Lovelace

Following up our recent analysis devoted to the impact of non steady accretion on the location of young low-mass stars or brown dwarfs in the Herzsprung-Russell diagram, we perform a detailed analysis devoted to the effect of burst…

Earth and Planetary Astrophysics · Physics 2015-05-19 Isabelle Baraffe , Gilles Chabrier

We study the formation of accretion disks resulting from dynamical three dimensional binary coalescence calculations, where a neutron star is tidally disrupted before being swallowed by its black hole companion. By subsequently assuming…

Astrophysics · Physics 2007-05-23 Enrico Ramirez-Ruiz , William H. Lee

We compute chemical evolution models to constrain the mode and the history of star formation in starburst galaxies as a whole, i.e. over a large range of mass and metallicity. To this end, we investigate the origin of the dispersion…

Astrophysics · Physics 2009-11-07 M. Mouhcine , T. Contini

We look at the spreading of localized temperature perturbations in the accreted fuel layer of a non-rotating neutron star. The pressure at the base of the accreted fuel layer is large and the material is only partially degenerate. Any…

A novel computational treatment of dense, stiff, coupled reaction rate equations is introduced to study the nucleation, growth, and possible coalescence of cavities during neutron irradiation of metals. Radiation damage is modeled by the…

Materials Science · Physics 2009-11-13 Michael P. Surh , Jess B. Sturgeon , Wilhelm G. Wolfer