Measure the electron temperature from the Balmer jump

Determine the electron temperature of the ionized gas in Vy 2-2 from the Balmer jump using observations with sufficient blue spectral coverage and accuracy.

Background

The paper derives electron temperatures and densities from several optical recombination-line ratios, but the Balmer-jump diagnostic could not be applied to the available spectra. The Balmer jump lies at the extreme blue edge of the observations, where the signal is too uncertain for a reliable measurement.

Obtaining this temperature would provide an independent physical diagnostic for the nebular gas and could help assess the consistency of the physical conditions inferred from collisionally excited and recombination lines.

References

We were not able to estimate an electron temperature from the Balmer jump.

— Intermediate- and high-resolution optical spectroscopy on the nascent planetary nebula Vy 2-2: Evidence of binary-star evolution  (2610.21988 - Cala et al., 15 Oct 2026) in Appendix A, “Physical conditions from optical recombination lines” (Sec. A; label sec:orl_physical)