Wind Roche lobe overflow as a way to make Type Ia supernovae from the widest symbiotic systems

Symbiotic stars are interacting binaries with one of the longest known orbital periods. Because they can contain a massive white dwarf with a high accretion rate they are considered possible Type Ia supernova (SN Ia) progenitors. Among symbiotic binaries there are systems containing a Mira donor, which can have orbital periods of a few tens of years or more. This subclass of symbiotic stars has not usually been considered to provide promising SN Ia progenitors owing to their very large separation. We analyse the evolution of a well-studied symbiotic star with a Mira donor, V407 Cyg, and show that the standard evolution model predicts that the system will not become a SN Ia. However, with the addition of wind Roche lobe overflow as one of the mass-transfer modes, we predict that the white dwarf in V407 Cyg will reach the Chandrasekhar limit in 40-200 Myr.