Determine whether the 16.46-day variability is pulsational or binary in origin

Determine whether the persistent 16.46-day radial-velocity variability of the blue supergiant ρ Leo is caused by non-radial pulsations, orbital motion induced by a companion, or a low-mass companion that influences the variability through tidal perturbations.

Background

The paper identifies a stable 16.46-day signal in the radial velocity and a weaker corresponding signal in the line-profile asymmetry of ρ Leo. The observations are more naturally explained by non-radial pulsations, but the signal’s long-term stability and synchronous shifts in multiple spectral lines remain compatible with an orbital interpretation.

The available observations do not decisively establish whether ρ Leo has a companion. In particular, the authors consider both a low-mass companion and a nearly pole-on massive companion, while noting that tidal interactions could modify the star’s pulsation spectrum and produce the observed transient features. Further observations are therefore required to determine whether binarity contributes to the observed variability.

References

Nevertheless, the possibility of a low-mass companion influencing the observed variability cannot be entirely excluded and warrants further investigation.

— A decade of radial-velocity monitoring of rho Leo: moment analysis and periodic variability  (2608.28039 - Checha et al., 28 Aug 2026) in Section 4.3, “Binarity as a Possible Origin of the Observed Variability”