Current accretion rate onto FQ Cir’s white dwarf

Ascertain the present mass accretion rate onto the 1.25 M⊙ white dwarf in FQ Circini using appropriate diagnostics (e.g., X-ray/UV spectroscopy or disk-emission modeling), as no usable constraints exist in the current data.

Background

The accretion rate is a key parameter for evaluating mass growth of the white dwarf and potential evolutionary outcomes (e.g., frequency of nova cycles, the onset of steady burning, or envelope expansion). The authors explicitly state that they lack usable evidence to determine the accretion rate for FQ Cir.

Robust constraints on the accretion rate would inform models of disk-to-disk mass transfer from the Be decretion disk to the white dwarf accretion disk in HMCVs.

References

Well, for FQ Cir, we have no useable evidence to know the accretion rate, but the two RRNe must have high accretion because they have very short recurrence timescales.

— FQ Circini: An Ordinary Nova with a High-mass B1 V(n)(e) Companion Whose Decretion Disk Transfers Mass to the White Dwarf via Roche-Lobe Overflow  (2511.16594 - Schaefer et al., 20 Nov 2025) in Section 4 (Supernova Progenitor?)