Betelgeuse (Alpha Orionis)

node · earth · Constellation Orion, as seen from Earth

The nearest red supergiant to the Sun and the clearest available example of a massive star in its final phase. Joyce and colleagues (2020) combined asteroseismic, evolutionary and hydrodynamic modelling of its 400-day pulsation to derive a mass of about 16.5 to 19 solar masses, a radius near 764 solar radii and a distance near 168 parsecs - about 548 light-years - and concluded that it is burning helium in its core with on the order of 100,000 years to go. Between October 2019 and March 2020 it faded by more than a magnitude in the visible in the episode known as the Great Dimming; imaging and modelling published in Nature in 2021 attributed it to a dust clump condensing above a cooled patch of the photosphere following a surface mass ejection. In 2025 a probable direct detection of a close stellar companion of roughly 1.5 solar masses was reported from speckle imaging, resolving a long-standing anomaly in its brightness variations. Not a place on Earth.