Light Curves and Spectra from a Thermonuclear Explosion of a White Dwarf Merger

Abstract

Double-degenerate (DD) mergers of carbon-oxygen white dwarfs have recently emerged as a leading candidate for normal Type Ia supernovae (SNe Ia). However, many outstanding questions surround DD mergers, including the characteristics of their light curves and spectra. We have recently identified a spiral instability in the post-merger phase of DD mergers and demonstrated that this instability self-consistently leads to detonation in some cases. We call this the spiral merger SN Ia model. Here, we utilize the SuperNu radiative transfer software to calculate three-dimensional synthetic light curves and spectra of the spiral merger simulation with a system mass of 2.1 $M_{\odot }$ from Kashyap et al. Because of their large system masses, both violent and spiral merger light curves are slowly declining. The spiral merger resembles very slowly declining SNe Ia, including SN 2001ay, and provides a more natural explanation for its observed properties than other SN Ia explosion models. Previous synthetic light curves and spectra of violent DD mergers demonstrate a strong dependence on viewing angle, which is in conflict with observations. Here, we demonstrate that the light curves and spectra of the spiral merger are less sensitive to the viewing angle than violent mergers, in closer agreement with observation. We find that the spatial distribution of 56Ni and IMEs follows a characteristic hourglass shape. We discuss the implications of the asymmetric distribution of 56Ni for the early-time gamma-ray observations of 56Ni from SN 2014J. We suggest that DD mergers that agree with the light curves and spectra of normal SNe Ia will likely require a lower system mass.

in ApJ 2016

References in corpus (18)

• The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star
• The Luminous and Carbon-Rich Supernova 2006gz: A Double Degenerate Merger?
• Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra
• Strong Ultraviolet Pulse From a Newborn Type Ia Supernova
• Extensive HST Ultraviolet Spectra and Multi-wavelength Observations of SN 2014J in M82 Indicate Reddening and Circumstellar Scattering by Typical Dust
• A Chandrasekhar Mass Progenitor for the Type Ia Supernova Remnant 3C 397 from The Enhanced Abundances of Nickel and Manganese
• The ejected mass distribution of type Ia supernovae: A significant rate of non-Chandrasekhar-mass progenitors
• Early 56Ni decay γ-rays from SN2014J suggest an unusual explosion
• The Viscous Evolution of White Dwarf Merger Remnants
• SN2014J gamma-rays from the 56Ni decay chain
• Measuring nickel masses in Type Ia supernovae using cobalt emission in nebular phase spectra
• Kepler's Supernova: An Overluminous Type Ia Event Interacting with a Massive Circumstellar Medium at a Very Late Phase
• Radiation Transport for Explosive Outflows: Opacity Regrouping
• Single-Degenerate Type Ia Supernovae Are Preferentially Overluminous
• Spiral Disk Instability Can Drive Thermonuclear Explosions in Binary White Dwarf Mergers
• Smoothed Particle Hydrodynamics simulations of the core-degenerate scenario for Type Ia supernovae
• 5.9 keV Mn K-shell X-ray luminosity from the decay of 55Fe in Type Ia supernova models
• The impact of chemical differentiation of white dwarfs on thermonuclear supernovae

Cited by in corpus (23)

• The X-ray counterpart to the gravitational wave event GW 170817
• The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
• Swift and NuSTAR observations of GW170817: detection of a blue kilonova
• Impact of ejecta morphology and composition on the electromagnetic signatures of neutron star mergers
• Axisymmetric Radiative Transfer Models of Kilonovae
• Double-Detonation Models for Type Ia Supernovae: Trigger of Detonation in Companion White Dwarfs and Signatures of Companions' Stripped-off Materials
• Multi-Dimensional Radiative Transfer Calculations of Double Detonations of Sub-Chandrasekhar-Mass White Dwarfs
• i-Process Contribution of Rapidly Accreting White Dwarfs to the Solar Composition of First-Peak Neutron-Capture Elements
• The white dwarf binary pathways survey - II. Radial velocities of 1453 FGK stars with white dwarf companions from LAMOST DR4
• SN2019yvq Does Not Conform to SN Ia Explosion Models
• A Significantly off-center Ni56 Distribution for the Low-Luminosity Type Ia Supernova SN 2016brx from the 100IAS survey
• Normal type Ia supernovae from disruptions of hybrid He-CO white-dwarfs by CO white-dwarfs
• A Rapid Ionization Change in the Nebular-Phase Spectra of the Type Ia SN 2011fe
• The Whisper of a Whimper of a Bang: 2400 Days of the Type Ia SN 2011fe Reveals the Decay of ${}^{55}$Fe
• Transient stellar collisions as multimessenger probes: Non-thermal-, gravitational wave emission and the cosmic ladder argument
• Common envelope to explosion delay time of type Ia supernovae
• Constraints on the physical properties of Type Ia supernovae from photometry
• One-Armed Spiral Instability in Double-Degenerate Post-Merger Accretion Disks
• Common envelope to explosion delay time distribution (CEEDTD) of type Ia supernovae
• Light Curves and Spectra from a Unimodal Core-Collapse SuperNova
• Merging White Dwarf Binaries Produce Type Ia Supernovae in Elliptical Galaxies
• Core-collapse supernova from a possible progenitor star of 100 M${}_{\odot }$
• Analyses of Hydrogen-stripped core-collapse supernovae using MOSFiT and MESA based tools