# Double Detonations with Thin, Modestly Enriched Helium Layers Can Make Normal Type Ia Supernovae

## TL;DR

This paper demonstrates through multi-dimensional simulations that thin, modestly enriched helium layers on white dwarfs can produce normal Type Ia supernovae via double detonations, supporting their role in supernova diversity.

## Contribution

First multi-dimensional full-star simulations show that modestly enriched thin helium layers can cause normal SNe Ia through double detonations, without artificial modifications.

## Key findings

- Normal SNe Ia can result from thin, modestly enriched helium layers.
- Double detonations are a viable major channel for normal SNe Ia.
- Simulations match observed spectra and brightness of typical SNe Ia.

## Abstract

It has been proposed that Type Ia supernovae (SNe Ia) that are normal in their spectra and brightness can be explained by a double detonation that ignites first in a helium shell on the surface of the white dwarf (WD). This proposition is supported by the satisfactory match between simulated explosions of sub-Chandrasekhar-mass WDs with no surface He layer and observations of normal SNe Ia. However, previous calculations of He-ignited double detonations have required either artificial removal of the He shell ashes or extreme enrichment of the surface He layer in order to obtain normal SNe Ia. Here we demonstrate, for the first time in multi-dimensional full-star simulations, that a thin, modestly enriched He layer will lead to a SN Ia that is normal in its brightness and spectra. This strengthens the case for double detonations as a major contributing channel to the population of normal SNe Ia.