Remnants of Binary White Dwarf Mergers

Raskin, Cody; Scannapieco, Evan; Fryer, Chris L.; Rockefeller, Gabriel; Timmes, F. X.

doi:10.1088/0004-637x/746/1/62

Cited by 115 publications

(152 citation statements)

References 51 publications

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“…This is consistent with the properties of hot spots seen in previous studies with less relaxed initial conditions (Pakmor et al 2010(Pakmor et al , 2011 and also with very recent simulations by Raskin et al (2011) who found similar hot spots in calculations with relaxed initial conditions and only slightly smaller resolution than our simulation. Note that Dan et al (2012) do not find hotspots in similar systems with exact initial conditions but more than a factor of ten fewer particles.…”

Section: Discussionsupporting

confidence: 94%

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

Pakmor

Kromer

Taubenberger

et al. 2012

ApJ

438

544

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One of the most important questions regarding the progenitor systems of Type Ia supernovae (SNe Ia) is whether mergers of two white dwarfs can lead to explosions that reproduce observations of normal events. Here we present a fully three-dimensional simulation of a violent merger of two carbon-oxygen white dwarfs with masses of 0.9M ⊙ and 1.1M ⊙ combining very high resolution and exact initial conditions. A well-tested combination of codes is used to study the system. We start with the dynamical inspiral phase and follow the subsequent thermonuclear explosion under the plausible assumption that a detonation forms in the process of merging. We then perform detailed nucleosynthesis calculations and radiative transfer simulations to predict synthetic observables from the homologously expanding supernova ejecta. We find that synthetic color lightcurves of our merger, which produces about 0.62M ⊙ of 56 Ni, show good agreement with those observed for normal SNe Ia in all wave bands from U to K. Line velocities in synthetic spectra around maximum light also agree well with observations. We conclude, that violent mergers of massive white dwarfs can closely resemble normal SNe Ia. Therefore, depending on the number of such massive systems available these mergers may contribute at least a small fraction to the observed population of normal SNe Ia.

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Section: Discussionsupporting

confidence: 94%

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

Pakmor

Kromer

Taubenberger

et al. 2012

ApJ

438

544

View full text Add to dashboard Cite

show abstract

“…combinations. This tendency of weak dependence on the resolution has already been reported in previous studies (Raskin et al 2012;Dan et al 2014). …”

Section: Numerical Resolutionsupporting

confidence: 86%

A SYSTEMATIC STUDY OF CARBON–OXYGEN WHITE DWARF MERGERS: MASS COMBINATIONS FOR TYPE Ia SUPERNOVAE

Sato

Nakasato

Tanikawa

et al. 2015

ApJ

108

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Mergers of two carbon-oxygen (CO) white dwarfs (WDs) have been considered to be progenitors of Type Ia supernovae (SNe Ia). Based on smoothed particle hydrodynamics (SPH) simulations, previous studies have claimed that mergers of CO WDs lead to SN Ia explosions either in the dynamical merger phase or the stationary rotating merger remnant phase. However, the mass range of CO WDs that lead to SNe Ia has notyet been clearly identified. In the present work, we perform systematic SPH merger simulations for the WD masses ranging from M 0.5  to M 1.1  with higher resolutions than the previous systematic surveys and examine whether or not carbon burning occurs dynamically or quiescently in each phase. We further study the possibility of SNe Ia explosions and estimate the mass range of CO WDs that lead to SNe Ia. We found that when both WDs are massive, i.e., in the mass range of ⩽ ⩽ and the total mass exceeds M 1.38  , they can finally explode in the stationary rotating merger remnant phase. We estimate the contribution of CO WD mergers to the entire SN Ia rate in our galaxy to be of 9%  . Thus, it might be difficult to explain all galactic SNe Ia with CO WD mergers.

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“…In particular, the envelopes of the two white dwarfs have often been neglected. While there are no simulations of mergers of He WDs with H-rich envelopes, there are simulations of mergers of COWDs with H-or helium-rich envelopes (Raskin et al 2012;Pakmor et al 2013). These CO+CO simulations could give some hints as to what He+He simulations with envelopes would look like.…”

Section: Merger Treatmentmentioning

confidence: 99%

Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

Hall

Jeffery

2016

Mon. Not. R. Astron. Soc.

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Isolated hot subdwarfs might be formed by the merging of two helium-core white dwarfs. Before merging, helium-core white dwarfs have hydrogen-rich envelopes and some of this hydrogen may survive the merger. We calculate the mass of hydrogen that is present at the start of such mergers and, with the assumption that hydrogen is mixed throughout the disrupted white dwarf in the merger process, estimate how much can survive. We find a hydrogen mass of up to about 2 × 10 −3 M in merger remnants. We make model merger remnants that include the hydrogen mass appropriate to their total mass and compare their atmospheric parameters with a sample of apparently isolated hot subdwarfs, hydrogen-rich sdBs. The majority of these stars can be explained as the remnants of double helium white dwarf mergers.

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Remnants of Binary White Dwarf Mergers

Cited by 115 publications

References 51 publications

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

A SYSTEMATIC STUDY OF CARBON–OXYGEN WHITE DWARF MERGERS: MASS COMBINATIONS FOR TYPE Ia SUPERNOVAE

Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

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