Explain the absence and changing strength of the spin signal

Determine why V844 Herculis lacks detectable optical-continuum and X-ray modulation at the inferred white-dwarf spin period during quiescence and explain the variation in the amplitude of its spin signal during superoutbursts.

Background

The intermediate-polar interpretation predicts signatures of magnetic accretion, yet the 29-minute signal is not detected in quiescent optical photometry or X-ray observations. In addition, the signal is strong early in superoutburst, weakens as superhumps develop, and later reappears before fading, a behavior the authors find difficult to reconcile with a simple accretion-flow origin.

The paper therefore leaves unresolved both the physical cause of the missing quiescent modulation and the mechanism controlling the changing amplitude of the spin signal during superoutbursts. These issues bear directly on the interpretation of V844 Herculis as an intermediate polar.

References

There are remaining questions about the IP interpretation for V844~Her. The lack of photometric modulation in the optical and X-rays during quiescence is puzzling. Also, the unexplained variation in the amplitude of the spin signal during superoutbursts is difficult to reconcile with accretion from the inner disk.

— V844 Herculis: An Exceptional Intermediate Polar Hiding in an Ordinary Dwarf Nova  (2609.26530 - Greiveldinger et al., 22 Sep 2026) in Section 5.4, “Evolution” and Conclusions