Fast and Luminous Transients from the Explosions of Long Lived Massive White Dwarf Merger Remnants

Abstract

We study the evolution and final outcome of long-lived ($\approx 10^5$ years) remnants from the merger of a He white dwarf (WD) with a more massive C/O or O/Ne WD. Using Modules for Experiments in Stellar Astrophysics ($\text{MESA}$), we show that these remnants have a red giant configuration supported by steady helium burning, adding mass to the WD core until it reaches $M_{\mathrm{core}}\approx 1.12-1.20M_{\odot }$. At that point, the base of the surface convection zone extends into the burning layer, mixing the helium burning products (primarily carbon and magnesium) throughout the convective envelope. Further evolution depletes the convective envelope of helium, and dramatically slows the mass increase of the underlying WD core. The WD core mass growth re-initiates after helium depletion, as then an uncoupled carbon burning shell is ignited and proceeds to burn the fuel from the remaining metal-rich extended envelope. For large enough initial total merger masses, O/Ne WD cores would experience electron-capture triggered collapse to neutron stars (NSs) after growing to near Chandrasekhar mass ($M_{\mathrm{Ch}}$). Massive C/O WD cores could suffer the same fate after a carbon-burning flame converts them to O/Ne. The NS formation would release $\approx 10^{50}$ ergs into the remaining extended low mass envelope. Using the STELLA radiative transfer code, we predict the resulting optical light curves from these exploded envelopes. Reaching absolute magnitudes of $M_V\approx -17$, these transients are bright for about one week, and have many features of the class of luminous, rapidly evolving transients studied by Drout and collaborators.

arXiv comment12 pages, 9 Figures, 1 Table

References in corpus (54)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Explosions of O-Ne-Mg Cores, the Crab Supernova, and Subluminous Type II-P Supernovae
• Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries
• Rapidly-Evolving and Luminous Transients from Pan-STARRS1
• A faint type of supernova from a white dwarf with a helium-rich companion
• Sub-Chandrasekhar Mass Models For Type Ia Supernovae
• Atomic Data for Permitted Resonance Lines of Atoms and Ions from H to Si, and S, Ar, Ca and Fe
• Helium-ignited violent mergers as a unified model for normal and rapidly declining Type Ia Supernovae
• Mass Transfer between Double White Dwarfs
• Theoretical light curves for deflagration models of Type Ia supernova
• Multi-Dimensional Simulations of the Accretion-Induced Collapse of White Dwarfs to Neutron Stars
• Surface Detonations in Double Degenerate Binary Systems Triggered by Accretion Stream Instabilities
• The Long-Term Evolution of Double White Dwarf Mergers
• Ultra-stripped Type Ic supernovae from close binary evolution
• Neutrino-driven supernova of a low-mass iron-core progenitor boosted by three-dimensional turbulent convection
• Low-temperature gas opacity - AESOPUS: a versatile and quick computational tool
• Supernova PTF 09uj: A possible shock breakout from a dense circumstellar wind
• Thermonuclear .Ia Supernovae from Helium Shell Detonations: Explosion Models and Observables
• The structure and fate of white dwarf merger remnants
• Rapidly Decaying Supernova 2010X: A Candidate ".Ia" Explosion
• Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap
• Very Large Excesses of 18O in Hydrogen-Deficient Carbon and R Coronae Borealis Stars: Evidence for White Dwarf Mergers
• The Ignition of Carbon Detonations via Converging Shock Waves in White Dwarfs
• Evolution towards and beyond accretion-induced collapse of massive white dwarfs and formation of millisecond pulsars
• An Unusually Fast-Evolving Supernova
• The Crab Nebula and the class of Type IIn-P supernovae caused by sub-energetic electron capture explosions
• Do electron-capture supernovae make neutron stars? First multidimensional hydrodynamic simulations of the oxygen deflagration
• The Merger Rate of Binary White Dwarfs in the Galactic Disk
• He-Accreting WDs: accretion regimes and final outcomes
• Every interacting double white dwarf binary may merge
• The Evolution and Fate of Super-Chandrasekhar Mass White Dwarf Merger Remnants
• Evolution of progenitors for electron capture supernovae
• Thermal Runaway During the Evolution of ONeMg Cores towards Accretion-Induced Collapse
• The Viscous Evolution of White Dwarf Merger Remnants
• Rapidly Rising Transients from Subaru Hyper Suprime-Cam Transient Survey
• Nickel-Rich Outflows from Accretion Disks Formed by the Accretion-Induced Collapse of White Dwarfs
• Double white dwarf mergers and elemental surface abundances in extreme helium and R Coronae Borealis stars
• The MACHO Project LMC Variable Star Inventory: X. The R Coronae Borealis Stars
• Nickel-Rich Outflows Produced by the Accretion-Induced Collapse of White Dwarfs: Lightcurves and Spectra
• Post-merger evolution of carbon-oxygen + helium white dwarf binaries and the origin of R Coronae Borealis and extreme helium stars
• Most Double Degenerate Low Mass White Dwarf Binaries Merge
• Rapidly Fading Supernovae from Massive Star Explosions
• Rapidly Evolving and Luminous Transients Driven by Newly Born Neutron Stars
• Carbon Shell or Core Ignitions in White Dwarfs Accreting from Helium Stars
• Turbulent Chemical Diffusion in Convectively Bounded Carbon Flames
• Rapidly evolving faint transients from stripped-envelope electron-capture supernovae
• Thermonuclear detonations ensuing white dwarf mergers
• Radio Transients from the Accretion Induced Collapse of White Dwarfs
• Reproducing the observed abundances in RCB and HdC stars with post-double degenerate merger models - constraints on merger and post-merger simulations and physics processes
• Can R CrB stars form from the merger of two helium white dwarfs?
• Accretion-Induced Collapse From Helium Star + White Dwarf Binaries
• R Coronae Borealis Stars are Viable Factories of Pre-solar Grains

Cited by in corpus (13)

• The Fast, Luminous Ultraviolet Transient AT2018cow: Extreme Supernova, or Disruption of a Star by an Intermediate-Mass Black Hole?
• Science objectives of the Einstein Probe mission
• FBOTs and AT2018cow following electron-capture collapse of merged white dwarfs
• Magnetar Engines in Fast Blue Optical Transients and Their Connections with SLSNe, SNe Ic-BL, and lGRBs
• AT2018kzr: the merger of an oxygen-neon white dwarf and a neutron star or black hole
• Optical follow-up observation of Fast Radio Burst 151230
• Type Ia Supernova Explosions from Hybrid Carbon-Oxygen-Neon White Dwarf Progenitors That Have Mixed During Cooling
• Late-time Hubble Space Telescope Observations of AT 2018cow. I. Further Constraints on the Fading Prompt Emission and Thermal Properties 50--60 Days Post-discovery
• The Formation of Electron-capture Supernovae: A Review
• Prospects for Time-Domain and Multi-Messenger Science with eXTP
• Laminar Flame Speeds in Degenerate Oxygen-Neon Mixtures
• A Population Study on the Radio Emission of Fast Blue Optical Transients
• Ultra-compact X-ray Binaries: A Review