Using ESO's Very Large Telescope (VLT), astronomers have captured an unprecedented darkening of Betelgeuse, a red supergiant star in the constellation Orion.
Stunning new images of the star's surface show not only the disappearing red supergiant, but also how its apparent shape is changing.
Betelgeuse was a beacon in the night sky for star watchers, but it began to fade late last year. At the time of this writing, Betelgeuse shines at 36% of its normal brightness, and this change is noticeable even to the naked eye. Astronomy buffs and scientists were enthusiastic about learning more about this unprecedented dimming.
The team, led by Miguel Montarges, an astronomer at KU Leuven University in Belgium, has been observing the star with ESO's Very Large Telescope since December to understand why it is getting fainter. Among the first observations is a stunning new image of the surface of Betelgeuse taken late last year with the SPHERE instrument.
The team also observed the star with the SPHERE in January 2019 before it started to fade, giving us a 'before and after' painting of Betelgeuse. Pictures taken in visible light highlight the changes taking place in the star in both brightness and visible form.
This image, taken with the VISIR instrument on ESO's Very Large Telescope, shows infrared light emitted by the dust surrounding Betelgeuse in December 2019. Dust clouds, reminiscent of the flames in this image, are formed when a star dumps its material into space. The black disk obscures the center of the star and much of its surroundings, which are very bright and must be masked in order to distinguish the weaker dust jets. Credit: ESO / P. Kervella / M. Montargès et al ., Acknowledgment: Eric Pantin
Many wondered if Betelgeuse's blackout meant it was about to explode. Like all red supergiants, Betelgeuse will go supernova one day, but astronomers don't think this is happening now. They have other hypotheses explaining what exactly causes the change in shape and brightness visible in the images.
“The two scenarios we are working on are surface cooling due to exceptional stellar activity or dust release,” says Montarges. “Of course, our knowledge of red supergiants remains incomplete, so a surprise may still occur.”
“The ESO Paranal Observatory is one of the few objects capable of capturing images of the surface of Betelgeuse,” he says. ESO's VLT instruments enable observations from the visible to mid-infrared range, which means astronomers can see both Betelgeuse's surface and the material around it.
“This is the only way to understand what is happening with the star.”
Sources: Photo: NASAESO / M. Montargès et al
