Radial velocity curve and component masses of FQ Cir

Obtain a phase-resolved radial velocity curve for FQ Circini—tracking the B1 V(n)(e) companion and, if possible, accretion-disk or white-dwarf features—to directly determine the component masses and orbital inclination.

Background

The paper derives masses and inclination from indirect constraints (main-sequence relations, blackbody radius, and ellipsoidal modulation). The authors explicitly note the absence of a radial velocity curve, which would provide direct dynamical measurements.

A radial velocity solution would refine the mass ratio, test the inferred 13 M⊙ companion and 1.25 M⊙ white dwarf, and improve understanding of ellipsoidal modulation amplitude and inclination.

References

We do not have any radial velocity curve to give us the stellar masses.

— 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 2.15 (Companion Mass)