Unresolved time evolution of spectral features during the outburst

Characterize the time evolution of the Balmer (Hβ, Hγ, Hδ) and He II λ4686 spectral features in AT2022kak during its 2025 outburst using higher signal-to-noise, time-resolved spectroscopy.

Background

KOALA provided 20-minute resolution spectra through the rise and fade of the 2025 outburst. Although key dwarf nova features are present, the low SNR limits the ability to track their temporal evolution.

A robust characterization of spectral feature evolution would test accretion disc instability models and clarify whether the outburst was inside-out or outside-in, and how line formation processes evolve during rapid events.

References

As the spectra have relatively low SNR, no conclusive comments can be made regarding feature evolution during outburst.

— An extremely fast fading population II dwarf nova candidate: caught spectroscopically on the rise (2510.26682 - Bemmel et al., 30 Oct 2025) in Section 4.2 (Spectral Analysis)