Multidimensional Radiative Transfer Calculations of Double Detonations of Sub-Chandrasekhar-mass White Dwarfs

Study of the double-detonation Type Ia supernova scenario, in which a helium-shell detonation triggers a carbon-core detonation in a sub-Chandrasekhar-mass white dwarf (WD), has experienced a resurgence in the past decade. New evolutionary scenarios and a better understanding of which nuclear reactions are essential have allowed for successful explosions in WDs with much thinner helium shells than in the original, decades-old incarnation of the double-detonation scenario. In this paper, we present the first suite of light curves and spectra from multidimensional radiative transfer calculations of thin-shell double-detonation models, exploring a range of WD and helium-shell masses. We find broad agreement with the observed light curves and spectra of nonpeculiar Type Ia supernovae, from subluminous to overluminous subtypes, providing evidence that double detonations of sub-Chandrasekhar-mass WDs produce the bulk of observed Type Ia supernovae. Some discrepancies in spectral velocities and colors persist, but these may be brought into agreement by future calculations that include more accurate initial conditions and radiation transport physics.

Automated summary

The study of double-detonation Type Ia supernova scenario has seen a resurgence in the past decade, with new evolutionary scenarios and a better understanding of essential nuclear reactions leading to successful explosions in white dwarfs with much thinner helium shells. Through multidimensional radiative transfer calculations, this study presents light curves and spectra from thin-shell double-detonation models, showing broad agreement with observed Type Ia supernovae across a range of WD and helium-shell masses. Some discrepancies in spectral velocities and colors remain, but may be addressed by future calculations with more accurate initial conditions and radiation transport physics.