SURFACE DETONATIONS IN DOUBLE DEGENERATE BINARY SYSTEMS TRIGGERED BY ACCRETION STREAM INSTABILITIES

By J. Guillochon, M. Dan, E. Ramirez-Ruiz, Stephan Rosswog. 2009

140 citations recorded by the source corpus.

We present three-dimensional simulations on a new mechanism for the detonation of a sub-Chandrasekhar CO white dwarf in a dynamically unstable system where the secondary is either a pure He white dwarf or an He/CO hybrid. For dynamically unstable systems where the accretion stream directly impacts the surface of the primary, the final tens of orbits can have mass accretion rates that range from 10−5 to 10−3 M☉ s−1, leading to the rapid accumulation of helium on the surface of the primary. After ∼10−2 M☉ of helium has been accreted, the ram pressure of the hot helium torus can deflect the accretion stream such that the stream no longer directly impacts the surface. The velocity difference between the stream and the torus produces shearing which seeds large-scale Kelvin–Helmholtz instabilities along the interface between the two regions. These instabilities eventually grow into dense knots of material that periodically strike the surface of the primary, adiabatically compressing the underlying helium torus. If the temperature of the compressed material is raised above a critical temperature, the timescale for triple-α reactions becomes comparable to the dynamical timescale, leading to the detonation of the primary's helium envelope. This detonation drives shock waves into the primary which tend to concentrate at one or more focal points within the primary's CO core. If a relatively small amount of mass is raised above a critical temperature and density at these focal points, the CO core may itself be detonated.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/f6ae97c73231c8ceccc384c3b49bd96b3584f7d0

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In Astronomy and Astrophysics

1. D. Kasen
2. Rüdiger Pakmor
3. F. Mannucci
4. D. Maoz
5. M. Kromer
6. E. Quataert
7. W. Hillebrandt
8. Friedrich K. Röpke

Citations in the corpus

• Type-Ia Supernova Rates and the Progenitor Problem: A Review (2011, background): “Sub-Chandrasekhar explosions have been proposed as a way of explaining some, or perhaps even most SN Ia events (Raskin et al. 2009; Rosswog et al. 2009; Sim et al. 2010; van Kekwijk, Chang & Justham 2010; Guillochon et al. 2010; Ruiter et al. 2011).”
• Observational Clues to the Progenitors of Type Ia Supernovae (2013, background): “Such “violent mergers” may lead to a SN Ia, even if the total mass of the merger is below MCh (Dan et al. 2013, Guillochon et al. 2010, Pakmor et al. 2013, Raskin et al. 2013, van Kerkwijk, Chang & Justham 2010, Zhu et al. 2013).”
• Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-degenerate Double-detonation Type Ia Supernovae (2018, background): “…SN Ia can be triggered during the coalescence itself due to the presence of helium in the surface layers of the companion WD, which initiates the SN Ia explosion via the double-detonation mechanism (Guillochon et al. 2010; Dan et al. 2011; Raskin et al. 2012; Pakmor et al. 2013; Dan et al. 2015).”
• HELIUM-IGNITED VIOLENT MERGERS AS A UNIFIED MODEL FOR NORMAL AND RAPIDLY DECLINING TYPE Ia SUPERNOVAE (2013, background): “It is resolved by cells with a radius of 30–40km. Note that the detonation forms dynamically, similar to previous results by Guillochon et al. (2010) for systems with high He accretion rates on CO primaries, rather than by thermal instabilities in stably-accreting steadily-burning systems (see,…”
• Sub-Chandrasekhar-mass White Dwarf Detonations Revisited (2017, background): “In parallel work, studies of unstable double WD mergers uncovered the possibility that helium could detonate as it was transferred during the dynamical phase of the merger (Guillochon et al. 2010; Raskin et al. 2012; Pakmor et al. 2013; Moll et al. 2014; Tanikawa et al. 2015).”
• DETONATIONS IN SUB-CHANDRASEKHAR-MASS C+O WHITE DWARFS (2010, background): “Detonations in helium-rich surface layers have also been discussed for the case of rapid dynamical mass transfer in binary systems containing a C+O WD with a helium-rich WD companion (Guillochon et al. 2010).”
• The delay-time distribution of Type Ia supernovae from Sloan II (2012, background): “CO WD mergers can indeed produce a SN Ia, which is still an open question (e.g. Guillochon et al. 2010; van Kerkwijk et al. 2010; Pakmor et al. 2011).”
• Violent mergers of nearly equal-mass white dwarf as progenitors of subluminous Type Ia supernovae (2011, background): “Note that a thermonuclear explosion may also be possible before the white dwarf reaches the Chandrasekhar-mass if the carbonoxygen white dwarf accretes helium from a non-degenerate or white dwarf companion (Fink et al. 2007, 2010; Sim et al. 2010; Guillochon et al. 2010).”
• THE LONG-TERM EVOLUTION OF DOUBLE WHITE DWARF MERGERS (2011, background): “We further assume that the extreme conditions necessary for a detonation are not met during the merger (Pakmor et al. 2010, 2011; Guillochon et al. 2010).”