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Title: The outcome of supernovae in massive binaries; removed mass, and its separation dependence

Abstract

The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this in mind, we have conducted two-dimensional hydrodynamical simulations of the collisions of CCSNe ejecta with the companion star in an almost-equal-mass (∼10 M {sub ☉}) binary to find out possible consequences of such events. In particular we pay attention to the amount of mass removed and its dependence on the binary separation. In contrast to the previous surmise, we find that the companion mass is stripped not by momentum transfer but by shock heating. Up to 25% of the original mass can be removed for the closest separations and the removed mass decreases as M {sub ub}∝a {sup –4.3} with the binary separation a. By performing some experimental computations with artificially modified densities of incident ejecta, we show that if the velocity of ejecta is fixed, the density of incident ejecta is the single important parameter that actually determines the removed mass as M{sub ub}∝ρ{sub ej}{sup 1.4}. On the other hand, another set of simulations with modified velocities ofmore » incident ejecta demonstrate that the strength of the forward shock, which heats up the stellar material and causes the mass loss of the companion star, is actually the key parameter for the removed mass.« less

Authors:
; ;  [1]
  1. Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan)
Publication Date:
OSTI Identifier:
22365168
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CALCULATION METHODS; DENSITY; LEAVES; MASS TRANSFER; MOMENTUM TRANSFER; SHOCK HEATING; SIMULATION; STELLAR WINDS; SUPERNOVAE; TWO-DIMENSIONAL CALCULATIONS; VELOCITY

Citation Formats

Hirai, Ryosuke, Sawai, Hidetomo, and Yamada, Shoichi. The outcome of supernovae in massive binaries; removed mass, and its separation dependence. United States: N. p., 2014. Web. doi:10.1088/0004-637X/792/1/66.
Hirai, Ryosuke, Sawai, Hidetomo, & Yamada, Shoichi. The outcome of supernovae in massive binaries; removed mass, and its separation dependence. United States. doi:10.1088/0004-637X/792/1/66.
Hirai, Ryosuke, Sawai, Hidetomo, and Yamada, Shoichi. Mon . "The outcome of supernovae in massive binaries; removed mass, and its separation dependence". United States. doi:10.1088/0004-637X/792/1/66.
@article{osti_22365168,
title = {The outcome of supernovae in massive binaries; removed mass, and its separation dependence},
author = {Hirai, Ryosuke and Sawai, Hidetomo and Yamada, Shoichi},
abstractNote = {The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this in mind, we have conducted two-dimensional hydrodynamical simulations of the collisions of CCSNe ejecta with the companion star in an almost-equal-mass (∼10 M {sub ☉}) binary to find out possible consequences of such events. In particular we pay attention to the amount of mass removed and its dependence on the binary separation. In contrast to the previous surmise, we find that the companion mass is stripped not by momentum transfer but by shock heating. Up to 25% of the original mass can be removed for the closest separations and the removed mass decreases as M {sub ub}∝a {sup –4.3} with the binary separation a. By performing some experimental computations with artificially modified densities of incident ejecta, we show that if the velocity of ejecta is fixed, the density of incident ejecta is the single important parameter that actually determines the removed mass as M{sub ub}∝ρ{sub ej}{sup 1.4}. On the other hand, another set of simulations with modified velocities of incident ejecta demonstrate that the strength of the forward shock, which heats up the stellar material and causes the mass loss of the companion star, is actually the key parameter for the removed mass.},
doi = {10.1088/0004-637X/792/1/66},
journal = {Astrophysical Journal},
number = 1,
volume = 792,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}
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  • Analysis of the theory of evolution of low- and intermediate-mass binaries allows us to select promising scenarios that lead to presupernova systems consisting of an accreting electron-degenerate dwarf (made primarily either of oxygen, neon, and magnesium, of carbon and oxygen, or of helium) and a low-mass (Mroughly-equalM/sub sun/) star supplying hydrogen-rich matter at rates in the range approx.10/sup -9/-10/sup -6/ M/sub sun/ yr/sup -1/ or a heavy disk composed of helium or of C and O supplying matter at an as yet undetermined rate. Some of these scenarios have an estimated frequency of realization comparable with the observed frequency (approx.10/supmore » -2/ yr/sup -1/) of Type I supernovae (SNeI), but it is as yet impossible to identify conclusively a single one as the most likely explanation of the SNI pheomenon and to reject all other possibilities. It is therefore not excluded that SNeI are a mixture of products of different scenarios. Estimates of formation frequency are very preliminary, since some of them are strongly dependent on the distribution of unevolved binaries over the initial mass ratio q/sub 0/, especially for q/sub 0/roughly-equal0.1--0.3, and most of them require knowledge of the processes that occur during a common envelope stage, the understanding of which is still very rudimentary.« less
  • The impact effects of supernova explosion on a low-mass (M< or =1 M/sub sun/) companion in a cataclysmic variable system are investigated with respect to variations in the companion mass and the density and velocity of the supernova shell. For the cases considered here, the incident kinetic energies of the shell were typically greater than the binding energy of the companion. Specific attention is focused on calculating the amount of momentum transferred to the companion star by the blast wave and by the nonplanar mass ablation that results. In no case was the binary system or companion disrupted. It ismore » found that the efficiency of momentum transfer is greater for less massive companions. However, if the reduction in the companion's cross sectional area due to mass stripping is included in the definition of the incident shell momentum, the efficiency for our most realistic sequences is found to be greater for the more massive companions. An expression for this effective efficiency is presented whicch agrees with the computational results to within 10%. The variations in the orbital parmeters are small if a high-mass (M> or =1.2M/sub sun/) neutron star remnant is left after the explosion. Angular momentum loss by gravitational radition gives a duration for the postexplosion detached binary phase (after which the system becomes an X-ray binary) of greater than 10/sup 8/ years. The center-of-mass velocity imparted to the postexplosion binary is small (< or =18 km s/sup -1/) and is consistent with the spatial distribution of the strong X-ray sources observed in highly condensed globular clusters and in the galactic disk.« less