Betelgeuse is considered a doomed star, and its explosion is only a matter of time. Observations from NASA’s Hubble Space Telescope show that the sudden darkening of the supergiant star Betelgeuse was most likely caused by the enormous amount of hot matter ejected into space, forming a dust cloud that blocked the starlight emanating from Betelgeuse’s surface.
The researchers speculate that the dust cloud was formed when superhot plasma released from the upward flow of a large convection cell on the star’s surface passed through the hot atmosphere into the colder outer layers, where it cooled down and formed dust particles. The resulting dust cloud has blocked light from about a quarter of the star’s surface since late 2019. By April 2020, the star has returned to normal brightness.
Betelgeuse is an aging red supergiant star that has grown in size due to complex evolutionary changes in its fusion furnace at its core. The star is now so huge that if it replaced the Sun at the center of our solar system, its outer surface would extend beyond Jupiter’s orbit.
Betelgeuse’s unprecedented strong blackout phenomenon, visible even to the naked eye, began in October 2019. By mid-February 2020, the monster star has lost more than two-thirds of its brilliance.
This sudden blackout has puzzled astronomers, who have tried to develop several theories of abrupt change.
Hubble recorded traces of dense, heated matter moving through the star’s atmosphere in September, October, and November 2019. Then, in December, several ground-based telescopes observed a decrease in the star’s brightness in the southern hemisphere.
“With the Hubble Telescope, we see material leaving the visible surface of the star and moving through the atmosphere before the dust was formed, which made the star appear dim,” said Dupree. “We could see the effect of a dense hot region moving in the southeastern part of the star.
“This material was two to four times brighter than the normal brightness of the star. And then, about a month later, the southern part of Betelgeuse became noticeably dimmer as the star became fainter. We think that it is possible that the dark cloud came from an explosion discovered by Hubble “.
The article was published August 13 in the Astrophysical Journal.