Identify the origin of the 353-day periodicity in L2 Pup

Identify the physical or observational origin of the approximately 353-day periodicity detected in the residual light curve of L$_2$ Pup, which is not accounted for by a harmonic or cross-harmonic of the confirmed pulsation behavior.

Background

After removing a model for the long-term dimming event, the analysis of L2_2 Pup identified a primary period near 139 days, an extra-long period near 6780 days, and an additional period of approximately 353 days.

The authors state that the 353-day signal cannot be explained as a harmonic or cross-harmonic because no confirmed multiperiodic behavior is present. Its origin therefore remains unresolved within the analysis.

References

The source of this period is unclear as it is not in the range of a harmonic or a cross-harmonic as there is no confirmed multiperiodic behaviour.

— Investigating the Light Curves of 5 Long Period Variable Stars: A Study Cross-Harmonics using VStar, MESA, and GYRE  (2609.08065 - Sherren et al., 8 Sep 2026) in Section 3, subsection “$L_2$ Pup”