The Role of Binary Configuration in Shaping Nova Evolution via Wind Accretion in Symbiotic Systems

Abstract We investigate the impact of the Bondi–Hoyle–Lyttleton (BHL) accretion mechanism on the evolution of nova eruptions in symbiotic systems by systematically varying three key input parameters: the initial donor (asymptotic giant branch, AGB) mass, the initial white dwarf (WD) mass, and the initial binary separation ( a ). We explore models with AGB masses in the range 1.5–3.5 M ⊙ , WD masses in the range 0.7–1.25 M ⊙ , and separations in the range 1000–8000 R ⊙ . We find all our models to show a significant, long-term orbital increase. This trend is primarily driven by the fact that ∼99% of the AGB’s mass is lost from the system, either directly via wind—that is never accreted onto the WD—or accreted onto the WD and then ejected during nova eruptions. This results in the effect of the mass loss (or transfer) on the orbit dominating over the effect of the angular momentum loss sinks that could shrink the orbit, leading to a consistent orbit widening. Consequently, all of our WD masses gradually decrease. A more massive WD achieves a higher mass transfer efficiency and accretion rate, meaning a slightly better mass retention efficiency per nova. However, since a higher accretion rate causes more frequent eruptions, the total WD mass loss over the AGB lifetime is more substantial. We conclude that symbiotic systems transferring mass via the BHL mechanism are unlikely to be Type Ia supernova progenitors.