2019MNRAS.489.4705J

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.