An extreme amplitude, massive heartbeat system in the LMC characterized using ASAS-SN and TESS

Abstract

Using ASAS-SN data, we find that the bright (V∼ 13.5 mag) variable star MACHO 80.7443.1718 (ASASSN-V J052624.38-684705.6) is the most extreme heartbeat star yet discovered. This massive binary, consisting of at least one early B-type star, has an orbital period of P_ASAS-SN=32.83627± 0.00846 d, and is located towards the LH58 OB complex in the LMC. Both the ASAS-SN and TESS light curves show extreme brightness variations of {∼ }40{{ per cent}} at periastron and variations of ∼ 10{{ per cent}} due to tidally excited oscillations outside periastron. We fit an analytical model of the variability caused by the tidal distortions at pericentre to find orbital parameters of ω =-61.4°, i=44.8°, and e=0.566. We also present a frequency analysis to identify the pulsation frequencies corresponding to the tidally excited oscillations.