scholarly journals Simulation of a compact object with outflows moving through a gaseous background

2020 ◽  
Vol 494 (2) ◽  
pp. 2327-2336 ◽  
Author(s):  
Xinyu Li ◽  
Philip Chang ◽  
Yuri Levin ◽  
Christopher D Matzner ◽  
Philip J Armitage
Keyword(s):  
Binary Systems ◽  
Accretion Rate ◽  
Compact Object ◽  
Quantitative Agreement ◽  
Compact Objects ◽  
Dynamical Friction ◽  
Hydrodynamic Simulations ◽  
Common Envelope ◽  
The Common ◽  
Classical Picture

ABSTRACT A compact object moving relative to surrounding gas accretes material and perturbs the density of gas in its vicinity. In the classical picture of Bondi–Hoyle–Lyttleton accretion, the perturbation takes the form of an overdense wake behind the object, which exerts a dynamical friction drag. We use hydrodynamic simulations to investigate how the accretion rate and strength of dynamical friction are modified by the presence of outflow from the compact object. We show that the destruction of the wake by an outflow reduces dynamical friction, and reverses its sign when the outflow is strong enough, in good quantitative agreement with analytic calculations. For a strong isotropic outflow, the outcome on scales that we have simulated is a negative dynamical friction, i.e. net acceleration. For jet-like outflows driven by reprocessed accretion, both the rate of accretion and the magnitude of dynamical friction drop for more powerful jets. The accretion rate is strongly intermittent when the jet points to the same direction as the motion of the compact object. The dynamical effects of outflows may be important for the evolution of compact objects during the common envelope phase of binary systems, and for accreting compact objects and massive stars encountering active galactic nucleus discs.

scholarly journals The Formation and Evolution of Compact Stars in Binaries

2004 ◽  
Vol 194 ◽  
pp. 81-84
Author(s):  
Ronald E. Taam
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Crucial Role ◽  
Binary Systems ◽  
Compact Objects ◽  
Compact Stars ◽  
Common Envelope ◽  
Formation And Evolution ◽  
The Common ◽  
Magnetic Braking

AbstractThe stellar evolutionary processes responsible for the formation of compact objects in interacting binary systems and their evolution are described. The common envelope phase plays a crucial role in their formation and angular momentum losses associated with magnetic braking and/or mass loss are important for their evolution. An application of these processes provides the evolutionary link between classes of interacting binary systems.

scholarly journals Accretion onto Relativistic Objects

1974 ◽  
Vol 64 ◽  
pp. 194-212
Author(s):  
M. J. Rees
Keyword(s):  
Black Holes ◽  
Interstellar Medium ◽  
Neutron Stars ◽  
Binary Systems ◽  
Compact Object ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Compact Objects ◽  
X Ray ◽  
Intergalactic Space

The physics of spherically symmetrical accretion onto a compact object is briefly reviewed. Neither neutron stars nor stellar-mass black holes are likely to be readily detectable if they are isolated and accreting from the interstellar medium. Supermassive black holes in intergalactic space may however be detectable. The effects of accretion onto compact objects in binary systems are then discussed, with reference to the phenomena observed in variable X-ray sources.

scholarly journals Progress of Common Envelope Evolution

1989 ◽  
Vol 8 ◽  
pp. 155-159
Author(s):  
R. E. Taam
Keyword(s):  
Binary System ◽  
Time Scale ◽  
Binary Systems ◽  
Efficiency Factor ◽  
Final Phase ◽  
Common Envelope ◽  
Orbital Decay ◽  
Mass Outflow ◽  
The Common ◽  
Orbital Periods

AbstractThe current understanding of the common envelope binary phase of evolution is presented. The results obtained from the detailed computations of the hydrodynamical evolution of this phase demonstrate that the deposition of energy by the double core via frictional processes is sufficiently rapid to drive a mass outflow, primarily in the equatorial plane of the binary system. Specifically, recent calculations suggest that large amounts of mass and angular momentum can be lost from the binary system in a such a phase. Since the time scale for mass loss at the final phase of evolution is much shorter than the orbital decay time scale of the companion, the tranformation of binary systems from long orbital periods (> month) to short orbital periods (< day) is likely. The energy efficiency factor for the process is estimated to lie in the range between 0.3 and 0.6.

scholarly journals Wind Accretion by Compact Objects: The “Flip-Flop” Instability

1992 ◽  
Vol 151 ◽  
pp. 185-194
Author(s):  
Mario Livio
Keyword(s):  
Random Walk ◽  
Accretion Rate ◽  
Compact Object ◽  
Two Dimensions ◽  
Compact Objects ◽  
Numerical Calculations ◽  
Three Dimensions ◽  
Flip Flop ◽  
Accretion Flows ◽  
The Stability

The problem of the stability of wind accretion onto compact objects is examined. Recent analytical and numerical calculations show that in two dimensions, Bondi-Hoyle accretion flows are unstable to a “flip-flop” instability. The instability can manifest itself as bursts in the accretion rate and as a random walk-type spin-up, spin-down behaviour of the accreting compact object. The nature of the flow in three dimensions needs further clarification. Possible observational implications are reviewed.

scholarly journals Negative dynamical friction on compact objects moving through dense gas

2020 ◽  
Vol 492 (2) ◽  
pp. 2755-2761 ◽  
Author(s):  
Andrei Gruzinov ◽  
Yuri Levin ◽  
Christopher D Matzner
Keyword(s):  
Black Holes ◽  
Binary Systems ◽  
Gaseous Medium ◽  
Stellar Mass ◽  
Compact Objects ◽  
Dense Gas ◽  
Dynamical Friction ◽  
Numerical Work ◽  
Massive Black Holes ◽  
Gas Drive

ABSTRACT An overdense wake is created by a gravitating object moving through a gaseous medium, and this wake pulls back on the object and slows it down. This is conventional dynamical friction in a gaseous medium. We argue that if the object drives a sufficiently powerful outflow, the wake is destroyed and instead an extended underdense region is created behind the object. In this case the overall gravitational force is applied in the direction of the object’s motion, producing a negative dynamical friction (NDF). Black holes in dense gas drive powerful outflows and may experience the NDF, although extensive numerical work is probably needed to demonstrate or refute this conclusively. NDF may be important for stellar-mass black holes and neutron stars inside ‘common envelopes’ in binary systems, for stellar mass black holes inside active galactic nucleus discs, or for massive black holes growing through super-Eddington accretion in early Universe.

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 Speaking with one voice: simulations and observations discuss the common envelope α parameter

2019 ◽  
Vol 490 (2) ◽  
pp. 2550-2566 ◽  
Author(s):  
Roberto Iaconi ◽  
Orsola De Marco
Keyword(s):  
Binary Interaction ◽  
Agb Stars ◽  
Recombination Energy ◽  
Intermediate Mass ◽  
Data Set ◽  
Hydrodynamic Simulations ◽  
Common Envelope ◽  
Upper Limits ◽  
Low Mass ◽  
The Common

ABSTRACT We present a comparative study between the results of most hydrodynamic simulations of the common envelope binary interaction to date and observations of post-common envelope binaries. The goal is to evaluate whether this data set indicates the existence of a formula that may predict final separations of post-common envelope systems as a function of pre-common envelope parameters. Some of our conclusions are not surprising while others are more subtle. We find that: (i) Values of the final orbital separation derived from common envelope simulations must at this time be considered upper limits. Simulations that include recombination energy do not seem to have systematically different final separations; these and other simulations imply αCE < 0.6–1.0. At least one simulation, applicable to double-degenerate systems, implies αCE < 0.2. (ii) Despite large reconstruction errors, the post-RGB observations reconstructed parameters are in agreement with some of the simulations. The post-AGB observations behave instead as if they had a systematically lower value of αCE. The lack of common envelope simulations with low-mass AGB stars leaves us with no insight as to why this is the case. (iii) The smallest mass companion that survives the common envelope with intermediate mass giants is 0.05–0.1 M⊙. (iv) Observations of binaries with separations larger than ∼10 R⊙, tend to have high M2/M1 mass ratios and may go through a relatively long phase of unstable Roche lobe mass transfer followed by a weakened common envelope (or with no common envelope at all). (v) The effect of the spatial resolution and of the softening length on simulation results remains poorly quantified.

scholarly journals Planetary Nebulae with binary nuclei

1997 ◽  
Vol 180 ◽  
pp. 74-84 ◽  
Author(s):  
Mario Livio
Keyword(s):  
High Resolution ◽  
Crucial Role ◽  
Binary Systems ◽  
Planetary Nebulae ◽  
Specific Mechanism ◽  
Essential Information ◽  
Common Envelope ◽  
High Resolution Images ◽  
The Common ◽  
Central Stars

High resolution images of planetary nebulae have revealed a variety of non-spherical morphologies. In addition, some planetary nebulae were found to produce highly collimated jets. It is argued that binary central stars may play a crucial role in the production of all of these morphologies. In particular, a specific mechanism is identified for the generation of “point-symmetric” nebulae. It is shown that the study of binary nuclei of planetary nebulae can provide essential information for the understanding of the common envelope phase in the evolution of binary systems.

scholarly journals Gravitational waves from in-spirals of compact objects in binary common-envelope evolution

2020 ◽  
Vol 493 (4) ◽  
pp. 4861-4867 ◽  
Author(s):  
Yonadav Barry Ginat ◽  
Hila Glanz ◽  
Hagai B Perets ◽  
Evgeni Grishin ◽  
Vincent Desjacques
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Compact Objects ◽  
Dynamical Friction ◽  
Next Generation ◽  
Common Envelope ◽  
Dissipative Processes

ABSTRACT Detection of gravitational-wave (GW) sources enables the characterization of binary compact objects (COs) and of their in-spiral. However, other dissipative processes can affect the in-spiral. Here, we show that the in-spiral of COs through a gaseous common envelope (CE) arising from an evolved stellar companion produces a novel type of GW sources, whose evolution is dominated by the dissipative gas dynamical friction effects from the CE, rather than the GW emission itself. The evolution and properties of the GW signals differ from those of isolated gas-poor mergers significantly. We find characteristic strains of ∼10−23–10−21 ($10\, {\rm kpc}/{D}$) for such sources – observable by next-generation space-based GW detectors (at rates of once per a few centuries for LISA, and about once a year for BBO). The evolution of the GW signal can serve as a probe of the interior regions of the evolved star, and the final stages of CE evolution, otherwise inaccessible through other observational means. Moreover, such CE mergers are frequently followed by observable explosive electromagnetic counterparts and/or the formation of exotic stars.

scholarly journals DOUBLE COMPACT OBJECTS. I. THE SIGNIFICANCE OF THE COMMON ENVELOPE ON MERGER RATES

2012 ◽  
Vol 759 (1) ◽  
pp. 52 ◽  
Author(s):  
Michal Dominik ◽  
Krzysztof Belczynski ◽  
Christopher Fryer ◽  
Daniel E. Holz ◽  
Emanuele Berti ◽  
...  
Keyword(s):  
Compact Objects ◽  
Common Envelope ◽  
The Common
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