Betelgeuse brightness dims as it enters helium-burning phase; not close to exploding: Study

Betelgeuse is the nearest red supergiant star to Earth. An aging, red star, it has swollen in size and developed complex and evolving changes in the nuclear fusion furnace at its core. According to NASA, if it replaced the Sun at the centre of the solar system, its outer surface would extend past Jupiter’s orbit. Researchers have recently observed that the star, which is usually one of the brightest in the winter sky, has shown an unprecedented drop in its brightness, leading to speculations that the star may be about to explode.

Researchers from Ken’ichi Nomoto at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) conducted a rigorous examination of the star and concluded that the star is in the early core helium-burning phase and has smaller mass and radius, and is closer to Earth, than earlier thought. They inferred from the study that the smaller brightness variations of the star were driven by pulsations and the dimming occurred due to a dust cloud.

 Betelgeuse brightness dims as it enters helium-burning phase; not close to exploding: Study

An illustration of how the Southern region of the rapidly evolving, bright red supergiant star Betelgeuse became fainter for several months during 2019-20. Image: NASA/ESA

The research team led by D Meridith Joyce from the Australian National University (ANU) analysed variations in brightness of Betelgeuse by using evolutionary hydronamic and seismic modelling. They reached the conclusion that the star is burning helium in its core. Researchers also pointed out that the stellar pulsations are causing the star to brighten or fade with two periods of 185 days and approximately 400 days.

The scientific results point towards that fact that the Betelgeuse is not at all close to exploding and that it is too far from Earth for the eventual explosion to have significant impact on the Blue planet.