Binary Evolution Pathways to Blue Large-Amplitude Pulsators: Insights from HD 133729

Blue Large-Amplitude Pulsators (BLAPs) represent a recently identified class of pulsating stars distinguished by their short pulsation periods (22-40 minutes) and asymmetric light curves. This study investigates the evolutionary channel of HD 133729, the first confirmed BLAP in a binary system. Through binary evolution simulations with MESA, we explored various mass ratios and initial orbital periods, finding that a mass ratio of q = 0.30 coupled with non-conservative mass transfer ($\rm \beta$ = 0.15) successfully reproduces the observational characteristics (including luminosity, surface gravity, and effective temperature) of the binary system. Our models not only match the observed pulsational properties but also predict significant helium and nitrogen enhancements on the surface of the main-sequence companion. The system is expected to eventually undergo a common envelope phase leading to a stellar merger. Our findings provide crucial insights into the formation mechanism and evolutionary fate of BLAPs with main-sequence companions, while also placing constraints on the elemental abundances of their binary companions.
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