That one is a really impressive article.

The accretion disc having been found, means that the companion star should also now be found.

The aspherical (non circular and spiral structure imprint) nature of the remnant indicates that the accretion disc was the feature shaping the remnant. The fact that it is a large accretion disc implies that the progenitor was an M giant & white dwarf symbiotic star similar to Mira or AG pegasi.

The companion star will be a VERY interesting find. It may have lost its outermost layers so is now likely to resemble a classical K giant.

If it remains an M giant it may well be visible as an IR object.

Have a nice day: Ag