Betelgeuse: Hidden Companion Photographed

Recent astronomical observations have revealed the presence of a hidden companion around the famous star Betelgeuse, one of the best-known stars in the constellation of Orion.

The discovery, published in The Astrophysical Journal Letters , was made possible by the new Gemini North telescope in Hawaii and is the work of a team led by Steve Howell of NASA's Ames Center.

Betelgeuse is one of the largest known stars, a red giant with a radius 800 times that of the Sun, and one of the brightest objects in the sky. It has attracted scientists' interest not only for its luminosity but also for its evolutionary state, which offers crucial clues to the life and death processes of the largest stars.

Located in the constellation Orion, Betelgeuse is visible to the naked eye, and astronomers have observed variations in its brightness over a period of approximately 400 days for millennia. Between 2019 and 2020, however, a sharp decline in brightness, greater than normal, was recorded: a phenomenon that led many to speculate its demise, a possible explosion in the near future as a supernova. But according to new data obtained from one of the innovative instruments on the Gemini North telescope, specifically the one called Alopeke, researchers have managed to observe the presence of a second, smaller star in a very close orbit to Betelgeuse. This faint glow had previously escaped all instruments because the light of the small star is obscured by the giant star.

According to the authors of the discovery, Betelgeuse's companion would have a mass about 1.5 times that of the Sun and would be so young that it has not yet begun burning hydrogen in its core. Furthermore, the companion would orbit at a very short distance, about four times the distance between the Earth and the Sun, so much so that it is practically within the red giant's atmosphere. The presence of this companion, the authors add, could explain Betelgeuse's various anomalies, because this very mass would periodically modify its outer disk, producing more or less marked variations in its brightness.

Recent studies also suggest that the presence of companions in complex star systems is not a rare phenomenon, and Betelgeuse may not be an isolated case. The implications of this discovery extend far beyond simple astronomical interest, as they also provide insights into planetary formation and the evolution of similar star systems.