Mechanism Selecting the Dominant BLAP Mode

Determine the mechanism that selects the dominant observable pulsation mode when several closely spaced frequencies are simultaneously present in a blue large-amplitude pulsator.

Background

OGLE-BLAP-142 and OGLE-BLAP-148 show year-scale exchanges in dominance among pulsation families separated by approximately one percent in period. These changes can mimic large period variations and are not explained by a single smoothly evolving pulsation period.

The observations demonstrate that relative mode amplitudes change, but they do not identify the process responsible for selecting or replacing the dominant mode. The problem is therefore relevant to understanding mode switching and the interpretation of apparent period changes in BLAPs.

References

More importantly, the mechanism that selects the dominant observable mode when several frequencies are present remains unknown.

— Mode Switching in Two Blue Large Amplitude Pulsators observed by OGLE, KMTNet and DREAMS  (2609.18300 - Ma et al., 16 Sep 2026) in Section 1, Introduction

The physical origin of these multiple frequencies and their switching mechanism remains unclear.

— Mode Switching in Two Blue Large Amplitude Pulsators observed by OGLE, KMTNet and DREAMS  (2609.18300 - Ma et al., 16 Sep 2026) in Section 5, Summary and Discussion