NASA says it has discovered the cause of the extraordinary darkening of the star Betelgeuse. The mysterious behavior of a bright star, in general, has led to theories ranging from dust obscurity to near-supernovae visible from Earth. However, working with the Hubble Space Telescope showed that this behavior was caused by a stellar "kiwi" that blocked the starlight and sent large amounts of hot matter into space. Betelgeuse is a relatively old, red superstar whose core is swollen due to nuclear fusion. It is so large that if it takes the place of our Sun, its surface extends across the orbit of Jupiter.
It is usually slightly brighter in our sky and is one of the most visible stars from Earth. But since October 2019, the marginal darkening can be seen even with the naked eye and its brightness has tripled. Astronomers could not account for the unusual behavior. Before it could be explained, it seemed to have stopped, and the star returned to its original brightness in April this year.
But looking at the historical data from the Hubble Space Telescope, which began in January last year, astronomers were able to create a timeline of what led to the darkening. Observations showed that the liquid was pushing through the star's atmosphere shortly before darkening. The researchers concluded that expulsion was the cause of the behavior that could not be explained in any other way. Other observations have shown that ultraviolet light behaves normally even when the star is dark. But scientists still cannot calculate the origin of the eruption or the cause of it. Researchers hope to study it further to better understand the processes that may take place around the star.