According to the latest round of observations, the notorious star Betelgeuse has ceased to manifest the dimming effect that many had hoped was a sure sign of a looming supernova effect, and is reported to actually be brightening.
"Photometry secured over the last ~2 weeks shows that Betelgeuse has stopped its large decline of delta-V of ~1.0 mag relative to September 2019," astronomers wrote in an Astronomers Telegram.
"Based on these and additional observations, Betelgeuse has definitely stopped dimming and has started to slowly brighten. Thus this 'fainting' episode is over but additional photometry is needed to define the brightening phase," added the scientists in their report entitled "The Fall and Rise in Brightness of Betelgeuse".
While the newest data signifies the celestial body is not about to explode in a premature death, this still leaves open the question as to why it had started dimming in the first place.
"Observations of all kinds continue to be needed to understand the nature of this unprecedented dimming episode and what this surprising star will do next," the astronomers wrote.
Asymmetrical Dimming Puzzle
Previously, Betelgeuse started making headlines as the naturally dimming variable star suddenly dimmed to its lowest for reasons still unknown to astronomers.
The recent dimming was far greater than any observed prior: between September 2019 and January 2020, it dimmed by 25 percent, generating a lot of excitement over hopes that it might be approaching an untimely demise.
Betelgeuse, situated in the Orion constellation about 700 light-years away, has surprised researchers with its longevity, as hot, bluish-white stars of this type, with a mass about 10 to 25 times that of the Sun typically enjoy short lifespans.
Currently 8 to 8.5 million years old, Betelgeuse’s main sequence days were done around 1 million years ago, with the orb cooling and transforming into a red supergiant about 40,000 years ago. By now, say astronomers, Betelgeuse has exhausted its supply of hydrogen in its core, and is fusing helium into carbon and oxygen.
The star's core will eventually fuse heavier elements, ultimately resulting in iron buildup that will cause the core to collapse in an explosion marking its demise.
However, astronomers predict that Betelgeuse still has some tens of thousands of years at its disposal, before a rapid dimming signals its approaching end.
Now Betelgeuse, known for its variable brightness, seems to have shelved hopes for a fiery spectacle in our lifetime, appearing to be returning to a more normal brightness level.
What Caused the Dimming?
Astronomers have been suggesting a number of explanations for the sudden dimming episode of Betelgeuse.
One of these is cooling on the stellar surface for some unknown to science reason.
Another is a giant dust cloud being ejected from the star towards Earth.
Stars of the red giant type create and eject vast amounts of material before they go supernova, and infrared images have shown Betelgeuse to be engulfed by plumes of dust.
Both of these explanations would be consistent with the asymmetry of the dimming, seen in images obtained in December 2019.
As the celestial object’s asymmetrical dimming continues to be the source of endless speculation by astronomers, they hope Betelgeuse could ultimately shed more light on the nature of this mysterious event.