This plot of V-band brightness shows Betelgeuse’s regular ~420-day pulsations, as well as the unprecedented dip in recent months. Red filled circles show the times of the three SOFIA/EXES observations compared in this study. [Harper et al. 2020]The unprecedented dimming of the red supergiant star Betelgeuse has been making headlines since late last year. To find out what’s causing it, an airplane-borne telescope took to the skies.
A Dramatic Decline
In October 2019, Betelgeuse — identifiable as the bright, massive red supergiant lying at the left shoulder of the constellation Orion — began declining in brightness. By February 2020, it had dimmed to less than 40% of its average luminosity, leading some to speculate that this star might be preparing to end its life as a dramatic supernova.
But Betelgeuse doesn’t appear to be going anywhere just yet. In February 2020, the star stopped dimming and started to climb in brightness again — and yet we still don’t know what caused its remarkable drop.
Betelgeuse, shown here in an infrared image from the Herschel Space Observatory, is a luminous red supergiant star located about 700 light-years away. [ESA/Herschel/PACS/L. Decin et al.]
The Role of Red Supergiants
Why do we ...