# Can the Helium-Enriched Main-Sequence Donor Scenario Hide Enough Hydrogen to Explain Type Ia Supernovae?

## TL;DR

This study investigates whether helium-enriched main-sequence donors can hide enough hydrogen to align with the low hydrogen detection in Type Ia supernovae, challenging existing progenitor models.

## Contribution

It introduces thermohaline mixing into binary evolution models for the HEMS donor channel, revealing higher hydrogen masses than observed limits.

## Key findings

- Hydrogen mass expected is 0.10-0.17 solar masses.
- Helium enrichment does not sufficiently reduce hydrogen mass.
- Challenges the viability of the HEMS donor channel for SNe Ia.

## Abstract

Hydrodynamical simulations predict that a large amount of hydrogen (>0.1 solar masses) is removed from a hydrogen-rich companion star by the SN explosion in the single-degenerate scenario of Type Ia supernovae (SNe Ia). However, non-detection of hydrogen-rich material in the late-time spectra of SNe Ia suggests that the hydrogen mass stripped from the progenitor system is <0.001-0.058 solar masses. In this letter we include thermohaline mixing into self-consistent binary evolution calculations for the helium-enriched main-sequence (HEMS) donor channel of SNe Ia for the first time. We find that the swept-up hydrogen masses expected in this channel are around 0.10-0.17 solar masses, which is higher than the observational limits, although the companion star is strongly helium-enriched when the SN explodes. This presents a serious challenge to the HEMS donor channel.