scholarly journals Simulations of disks in binary systems using parallelized SPH to reach extreme spatial resolution

2003 ◽  
Vol 208 ◽  
pp. 427-428
Author(s):  
D. Molteni ◽  
F. Fauci ◽  
G. Gerardi ◽  
M. A. Valenza
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Numerical Simulations ◽  
Spatial Resolution ◽  
Spectral Properties ◽  
Binary Systems ◽  
Compact Star ◽  
Close Binary ◽  
Gas Transfer ◽  
Set Up

Results of 3D numerical simulations of the gas transfer in close binary systems show that it is possible the production of accretion streams having low specific angular momentum in a region close to the accreting star. These streams are mainly placed above the orbital disc. The eventual formation of such bulges and shock heated flows is interesting in the context of advection dominated solutions and for the explanation of spectral properties of the Black Hole candidates in binary systems. We set up a parallelized version of 3D S.P.H. code, using domain decomposion. with increasing spatial resolution around the compact star.

scholarly journals The Interaction of Binary Systems with Accretion Disks

2004 ◽  
Vol 191 ◽  
pp. 202-203
Author(s):  
Manuel Ortega-Rodríguez
Keyword(s):  
Angular Momentum ◽  
Accretion Disks ◽  
Binary Systems ◽  
Compact Star ◽  
Companion Star ◽  
X Ray ◽  
Outgoing Radiation

AbstractWe study the (time) fluctuations in the outgoing radiation of accretion disks in binary systems in order to obtain properties of those systems (via comparison with observations), such as the angular momentum of the compact star within the disk. The effects of the companion star are discussed, and a prediction is made on the frequency of the outgoing (modulated) X-ray radiation.

scholarly journals Effects of Rotation on Helium Accreting White Dwarf

2004 ◽  
Vol 215 ◽  
pp. 571-572 ◽  
Author(s):  
S.-C. Yoon ◽  
N. Langer
Keyword(s):  
Angular Momentum ◽  
White Dwarf ◽  
Spherical Symmetry ◽  
Binary Systems ◽  
Close Binary ◽  
Type Ia Supernovae ◽  
Classical Studies ◽  
Type Ia ◽  
Effects Of Rotation ◽  
Ia Supernovae

Classical studies of accreting white dwarfs have assumed spherical symmetry. However, it is believed that in close binary systems the transfered matter carries angular momentum to spin up the accreting star. Here, we present preliminary results of CO white dwarf models which accrete helium rich matter with effects of rotation considered, in the context of the Sub-Chandrasekhar mass scenario for Type Ia supernovae.

scholarly journals CLOSE BINARY PROGENITORS OF HYPERNOVAE

2012 ◽  
Vol 08 ◽  
pp. 209-219 ◽  
Author(s):  
MAXIM V. BARKOV
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Neutron Star ◽  
Binary Systems ◽  
Close Binary ◽  
Transient Event ◽  
Common Envelope ◽  
Starting Point ◽  
The Common ◽  
Rayet Star

In this paper we propose a new plausible mechanism of supernova explosions specific to close binary systems. The starting point is the common envelope phase in the evolution of a binary consisting of a red super giant and a neutron star. As the neutron star spirals towards the center of its companion it spins up via disk accretion. Depending on the specific angular momentum of gas captured by the neutron star via the Bondi-Hoyle mechanism, it may reach millisecond periods either when it is still inside the common envelope or after it has merged with the companion core. The high accretion rate may result in strong differential rotation of the neutron star and generation of a magnetar-strength magnetic field. The magnetar wind can blow away the common envelope if its magnetic field is as strong as 1015 G, and can destroy the entire companion if it is as strong as 1016 G. The total explosion energy can be comparable to the rotational energy of a millisecond pulsar and reach 1052 erg. The result is an unusual type-II supernova with very high luminosity during the plateau phase, followed by a sharp drop in brightness and a steep light-curve tail. The remnant is either a solitary magnetar or a close binary involving a Wolf-Rayet star and a magnetar. When this Wolf-Rayet star explodes this will be a third supernovae explosion in the same binary. A particularly interesting version of the binary progenitor involves merger of a red super giant star with an ultra-compact companion, neutron star or black hole. In the case if a strong magnetic field is not generated on the surface of a neutron star then it will collapse to a black hole. After that we expect the formation of a very long-lived accretion disk around the black hole. The Blandford-Znajek driven jet from this black hole may drive not only hypernovae explosion but produce a bright X-ray transient event on a time scale of 104 s.

scholarly journals Energy optimization in binary star systems: explanation for equal mass members in close orbits

2020 ◽  
Vol 494 (2) ◽  
pp. 2289-2298 ◽  
Author(s):  
Fred C Adams ◽  
Konstantin Batygin ◽  
Anthony M Bloch
Keyword(s):  
Angular Momentum ◽  
Binary Systems ◽  
Energy State ◽  
Binary Star ◽  
Minimum Energy ◽  
Semimajor Axis ◽  
Theoretical Explanation ◽  
Equal Mass ◽  
Close Binary ◽  
Ratio Distribution

ABSTRACT 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 by determining the tidal equilibrium states for binary star systems – subject to the constraints of conservation of angular momentum and constant total mass. This work generalizes previous treatments by including the mass fraction as a variable in the optimization problem. The results show that the lowest energy state accessible to the system corresponds to equal mass stars on a circular orbit, where the stellar spin angular velocities are both synchronized and aligned with the orbit. These features are roughly consistent with observed properties of close binary systems. We also find the conditions required for this minimum energy state to exist: (1) the total angular momentum must exceed a critical value, (2) the orbital angular momentum must be three times greater than the total spin angular momentum, and (3) the semimajor axis is bounded from above. The last condition implies that sufficiently wide binaries are not optimized with equal mass stars, where the limiting binary separation occurs near a0 ≈ 16R*.

scholarly journals The Evolution of Massive Close Binary Systems : Estimates of the Parameters Governing Mass and Angular Momentum Loss

1980 ◽  
Vol 88 ◽  
pp. 115-121
Author(s):  
D. Vanbeveren ◽  
C. De Loore
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Binary Systems ◽  
Mass Loss Rate ◽  
Roche Lobe ◽  
Close Binary ◽  
Close Binaries ◽  
Stellar Winds ◽  
Binary Evolution ◽  
Image Position

It becomes more and more evident that for close binary evolution during Roche lobe overflow as well mass transfer as mass loss occurs. When a mass element ΔM is expelled from the primary during this phase, a fraction β is transferred to the secondary; the remaining part leaves the system. Moreover, angular momentum leaves the system, and also this fraction has to be specified; this fraction is related to a parameter α (Vanbeveren et al., 1979). For the computation of the evolution of massive close binaries also mass loss due to stellar wind of both components, prior to the Roche lobe overflow has to be taken into account. The mass loss rate Ṁ due to radiation driven stellar winds can be expressed as

scholarly journals Evolution of Rotating White Dwarfs in Close Binaries and Diversity of Type Ia Supernovae

2003 ◽  
Vol 208 ◽  
pp. 459-460
Author(s):  
Tatsuhiro Uenishi ◽  
Ken'ichi Nomoto ◽  
Izumi Hachisu
Keyword(s):  
Angular Momentum ◽  
Accretion Disk ◽  
White Dwarf ◽  
Binary Systems ◽  
Close Binary ◽  
Close Binaries ◽  
Type Ia Supernovae ◽  
Rapid Rotation ◽  
Type Ia ◽  
Ia Supernovae

Type Ia supernovae are very good, but not perfect, standard candles, because their observed brightness shows a little diversity. The origin of this dibersity needs to be understood for the application to cosmology.In close binary systems, a white dwarf must be rotating faster and faster as it gains angular momentum from the accretion disk. Its rapid rotation affects its final mass and strucure just before a supernova expolosion. Brightness of supernovae can be changed if mass of their progenitors have some diversity.

scholarly journals Late Stages of Close Binary Systems

1976 ◽  
Vol 73 ◽  
pp. 35-61 ◽  
Author(s):  
E. P. J. Van Den Heuvel
Keyword(s):  
Angular Momentum ◽  
Mass Exchange ◽  
Binary Systems ◽  
Main Sequence ◽  
Supernova Explosion ◽  
Compact Stars ◽  
Close Binary ◽  
Close Binaries ◽  
X Ray ◽  
Loss Of Mass

The expected final evolution of massive close binaries (CB) in case B is reviewed. Primary stars with masses ≳ 12–15 M⊙ are, after loosing most of their envelope by mass exchange, expected to explode as supernovae, leaving behind a neutron star or a black hole.Conservative close binary evolution (i.e. without a major loss of mass and angular momentum from the system during the first stage of mass transfer) is expected to occur if the initial mass ratio q0 = M20/M10 is ≳ 0.3. In this case the primary star will be the less massive component when it explodes, and the system is almost never disrupted by the explosion. The explosion is followed by a long-lasting quiet stage (106–107 yr) when the system consists of a massive main-sequence star and an inactive compact companion. After the secondary has left the main-sequence and becomes a blue supergiant with a strong stellar wind, the system becomes a massive X-ray binary for a short while (2–5 × 104 yr).The numbers of Wolf-Rayet binaries and massive X-ray binaries observed within 3 kpc of the Sun are in reasonable agreement with the numbers expected on the basis of conservative CB evolution, which implies that several thousands of massive main-sequence stars with a quiet compact companion should exist in the Galaxy. About a dozen of these systems must be present among the stars visible to the naked eye. During the second stage of mass exchange, large loss of mass and angular momentum from the system is expected, leading to a rapid shrinking of the orbit. The supernova explosion of the secondary will in most cases disrupt the system. If it remains bound, the final system will consist of two compact stars and may resemble the binary pulsar PSR 1913 + 16.In systems with q0 ≲ 0.2–0.3 large mass loss from the system is expected during the first stage of mass exchange. The exploding primary will then be more massive than its unevolved companion and the first supernova explosion disrupts the system in most cases. In the rare cases that it remains bound, the system will have a large runaway velocity and, after a very long (108–109 yr) inactive stage evolves into a low-mass X-ray binary, possibly resembling Her X-1.

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