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.
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