# Spectral analysis of the binary nucleus of the planetary nebula Hen 2-428 - first results

## TL;DR

This paper presents the first detailed spectral analysis of the planetary nebula Hen 2-428's binary core, providing key parameters that help evaluate its potential as a type Ia supernova progenitor.

## Contribution

It offers the first quantitative spectral analysis of Hen 2-428's central stars using advanced non-LTE models, informing future studies on its supernova progenitor status.

## Key findings

- Derived effective temperatures and surface gravities of the central stars.
- Estimated helium abundances in the binary system.
- Provides constraints for future evolutionary and supernova progenitor models.

## Abstract

Identifying progenitor systems for the double-degenerate scenario is crucial to check the reliability of type Ia super-novae as cosmological standard candles. Santander-Garcia et al. (2015) claimed that Hen 2-428 has a double-degenerate core whose combined mass significantly exceeds the Chandrasekhar limit. Together with the short orbital period (4.2 hours), the authors concluded that the system should merge within a Hubble time triggering a type Ia supernova event. Garcia-Berro et al. (2016) explored alternative scenarios to explain the observational evidence, as the high mass conclusion is highly unlikely within predictions from stellar evolution theory. They conclude that the evidence supporting the supernova progenitor status of the system is premature. Here we present the first quantitative spectral analysis of Hen 2-428 which allows us to derive the effective temperatures, surface gravities and helium abundance of the two CSPNe based on state-of-the-art, non-LTE model atmospheres. These results provide constrains for further studies of this particularly interesting system.