The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries

The recent prediction and discovery of hypervelocity supernova survivors has provided strong evidence that the “dynamically driven double-degenerate double-detonation” (D ^6 ) Type Ia supernova scenario occurs in nature. In this model, the accretion stream from the secondary white dwarf (WD) in a do...

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Main Author: Ken J. Shen
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adb42e
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author Ken J. Shen
author_facet Ken J. Shen
author_sort Ken J. Shen
collection DOAJ
description The recent prediction and discovery of hypervelocity supernova survivors has provided strong evidence that the “dynamically driven double-degenerate double-detonation” (D ^6 ) Type Ia supernova scenario occurs in nature. In this model, the accretion stream from the secondary white dwarf (WD) in a double WD binary strikes the primary WD violently enough to trigger a helium shell detonation, which in turn triggers a carbon/oxygen core detonation. If the secondary WD survives the primary’s explosion, it will be flung away as a hypervelocity star. While previous work has shown that the hotter observed D ^6 stars can be broadly understood as secondaries whose outer layers have been heated by their primaries’ explosions, the properties of the cooler D ^6 stars have proven difficult to reproduce. In this paper, we show that the cool D ^6 stars can be explained by the Kelvin–Helmholtz contraction of helium or carbon/oxygen WDs that underwent significant mass loss and core heating prior to and during the explosion of their WD companions. We find that the current population of known D ^6 candidates is consistent with ∼2% of Type Ia supernovae leaving behind a hypervelocity surviving companion. We also calculate the evolution of hot, low-mass oxygen/neon stars and find reasonable agreement with the properties of the LP 40–365 class of hypervelocity survivors, suggesting that these stars are the kicked remnants of near-Chandrasekhar-mass oxygen/neon WDs that were partially disrupted by oxygen deflagrations. We use these results as motivation for schematic diagrams showing speculative outcomes of interacting double WD binaries, including long-lived merger remnants, Type Ia supernovae, and several kinds of peculiar transients.
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spelling doaj-art-d7fa28174afd4cfa81c6b44be5282f8f2025-08-20T02:57:53ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-019821610.3847/1538-4357/adb42eThe Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf BinariesKen J. Shen0https://orcid.org/0000-0002-9632-6106Department of Astronomy and Theoretical Astrophysics Center, University of California , Berkeley, CA 94720, USA ; kenshen@astro.berkeley.eduThe recent prediction and discovery of hypervelocity supernova survivors has provided strong evidence that the “dynamically driven double-degenerate double-detonation” (D ^6 ) Type Ia supernova scenario occurs in nature. In this model, the accretion stream from the secondary white dwarf (WD) in a double WD binary strikes the primary WD violently enough to trigger a helium shell detonation, which in turn triggers a carbon/oxygen core detonation. If the secondary WD survives the primary’s explosion, it will be flung away as a hypervelocity star. While previous work has shown that the hotter observed D ^6 stars can be broadly understood as secondaries whose outer layers have been heated by their primaries’ explosions, the properties of the cooler D ^6 stars have proven difficult to reproduce. In this paper, we show that the cool D ^6 stars can be explained by the Kelvin–Helmholtz contraction of helium or carbon/oxygen WDs that underwent significant mass loss and core heating prior to and during the explosion of their WD companions. We find that the current population of known D ^6 candidates is consistent with ∼2% of Type Ia supernovae leaving behind a hypervelocity surviving companion. We also calculate the evolution of hot, low-mass oxygen/neon stars and find reasonable agreement with the properties of the LP 40–365 class of hypervelocity survivors, suggesting that these stars are the kicked remnants of near-Chandrasekhar-mass oxygen/neon WDs that were partially disrupted by oxygen deflagrations. We use these results as motivation for schematic diagrams showing speculative outcomes of interacting double WD binaries, including long-lived merger remnants, Type Ia supernovae, and several kinds of peculiar transients.https://doi.org/10.3847/1538-4357/adb42eSupernovaeWhite dwarf starsHypervelocity stars
spellingShingle Ken J. Shen
The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
The Astrophysical Journal
Supernovae
White dwarf stars
Hypervelocity stars
title The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
title_full The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
title_fullStr The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
title_full_unstemmed The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
title_short The Evolution of Hypervelocity Supernova Survivors and the Outcomes of Interacting Double White Dwarf Binaries
title_sort evolution of hypervelocity supernova survivors and the outcomes of interacting double white dwarf binaries
topic Supernovae
White dwarf stars
Hypervelocity stars
url https://doi.org/10.3847/1538-4357/adb42e
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