MACHO 80.7443.1718

MACHO 80.7443.1718
Observation data; Epoch Equinox
Constellation	Dorado
Right ascension	05h 26m 24.462s
Declination	−68° 47′ 04.941″
Apparent magnitude (V)	13.628
Characteristics
Evolutionary stage	Main-sequence star
Spectral type	B0 Iae + O9.5 V
Variable type	Heartbeat star
mas/yr
Semi-amplitude (K1); (primary)	61.9±2.8 km/s
Details
B
Mass	15.7±1.3 M☉
Radius	5.7+0.4; −0.5 R☉
Luminosity	2.88+0.83; −0.70×104 L☉
Surface gravity (log g)	4.1±0.1 cgs
Temperature	31600±1000 K
TIC 373840312, GMP94 100, Gaia DR2 4658489067332871552, Gaia DR3 4658489067332871552

MACHO 80.7443.1718 is a binary star in the LH 58 association in the Large Magellanic Cloud, in the constellation of Dorado, first identified among about 800 stars in 1994.^[3] It consists of a 35 M_☉ blue supergiant in an eccentric orbit with a secondary companion that cannot be observed directly, but is likely an O-type main-sequence star of around 15 M_☉.^[2]

It is the most extreme

oblate spheroid.^[5]^[6]

The system's orbit is slowly decaying as

Abraham Loeb and Morgan MacLeod of the Harvard–Smithsonian Center for Astrophysics to describe MACHO 80.7443.1718 as a "heartbreak star".^[7] Jayasinghe et al. (2021) modeled the system and predicted that the primary will eventually overflow its Roche lobe and deposit mass onto the secondary, inflating its mass to 24 M_☉. The primary will eventually go supernova and become a black hole of about 8 M_☉, but the explosion would not be strong enough to eject the secondary. The secondary will become a 12 M_☉ helium star, and be ejected from the system when it goes supernova as well, leaving a 1.6 M_☉ neutron star remnant.^[2] However, according to Susan Mallally at the Space Telescope Science Institute, the heartbeat mass transfer may influence the system's evolution in ways that cannot be predicted using current models.^[7]