The material that the dwarf is accreting surely comes from the giant, which like all Mira stars is shedding a thick wind
A few weeks later, on June 27th, that far-ultraviolet light had mostly disappeared, probably because the companion star had swung behind the primary and was eclipsed by its thick wind
. The timing of the disappearance coincided perfectly with the binary model's predictions.
continually poured off the progenitors of such stars, flooding their surroundings and draining the outer layers of the Wolf-Rayet stars," NASA said.