The red supergiant Betelgeuse, one of the brightest stars in the night sky and a member of the Orion constellation, has once again sparked interest among astronomers due to a new decline in its luminosity. Located approximately 650 light-years from Earth, this celestial body presented a significant change in August when its magnitude shifted from +0.5 to 0.95. Although this numerical difference may appear small, it was sufficient for Betelgeuse to appear dimmer than its neighbor Aldebaran in the Taurus constellation. Scientists consider this variation important as it may signal specific processes occurring within the star.
The variability of Betelgeuse has been documented since 1836. Current scientific understanding indicates that the star undergoes diverse processes, including periodic internal contractions, colossal dust eruptions, and gravitational interference from other celestial bodies. These cyclic oscillations stem from its advanced stage of stellar evolution, causing it to pulse continuously. As a supergiant nearing the end of its life cycle, Betelgeuse experiences regular pulsation cycles lasting approximately 430 days. Astronomer Henry M. Neely described this behavior as the star expanding and contracting with spasms, likening it to an elderly man gasping for breath at the end of his life.
During the expansion phase, the star's outer layers lose temperature and reduce light emission. Conversely, during contraction, heat concentrates, allowing the star to reach intensity peaks comparable to 14,000 suns, making its behavior dynamic and unpredictable to the naked eye. A significant development in unraveling this phenomenon occurred in early 2026 through joint observations by the Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in the Atacama Desert, Chile.
These instruments captured direct evidence of a subtle companion star orbiting the supergiant. Formally named Alpha Ori B, this stellar partner interacts gravitationally with the dust and gas surrounding Betelgeuse. Researchers suggest that this companion may be the missing piece needed to explain the star's longer dimming cycles.
Sources: Canaltech.