Origin of the E202104 eruption in VY Scl stars

Determine why eruptive events analogous to E202104 have been observed in only a small fraction of VY Scl stars.

Background

The eruption E202104 occurred concurrently with the collapse of J0727’s accretion disk and has an unusual 45-day duration and energy comparable to that of dwarf-nova superoutbursts. The paper argues that it cannot be straightforwardly explained by mass-transfer variations, disk thermal instability, or thermonuclear burning, and speculates that gravitational energy released during disk contraction powers it. The frequency of similar events among VY Scl stars remains unexplained.

References

However, it remains unclear why similar events have so far been observed only in a small fraction of VY Scl stars.

— Dynamically driven collapse of a thermally stable accretion disk in a nova-like system  (2608.27878 - Li et al., 28 Aug 2026) in Section 3.2, Discussion, “Prolonged eruptive event during the disk collapse”