Why Betelgeuse was suddenly losing its shine?
The unexpected and significant Deming periods of Betelgeuse in late 2019 and early 2020 has puzzled astronomers around the world. Some believed that it signaled the star’s upcoming explosion but then the dimming abruptly stopped thanks to observations by NASA’s Hubble telescope we now know that the dimming periods were most likely caused by the ejection and cooling of dense hot gases.
The night sky might appear as if it never changes, but, if you look close enough, there’s always something happening out there. Back in February, we saw about some strange observations astronomers had fabricated from our neighboring star Betelgeuse. As a red supergiant, Betelgeuse is essentially a large bomb waiting to travel off, so it definitely got scientists’ attention when its brightness started suddenly changing in late 2019. Over the course of some months, the star’s brightness dropped by an element of three—and the southern half gave the impression to darken more dramatically than the north. It had many people wondering if it absolutely was preparing to explode. Then, in April, things just… returned to normal.
Now, due to the Hubble Space Telescope, we finally have a clue what might need happened. In work published last week within the Astrophysical Journal, a world research team described observations that suggest the culprit may need been a cloud of dust that launched from the star itself. Some months before Betelgeuse started acting up, the team began using Hubble to form regular observations of the star as a part of a long-term study on variability in its outer layers. And starting in September 2019—just weeks before the star dimmed dramatically—this team detected a pulse of fabric moving outwards through the southern 1/2 Betelgeuse’s atmosphere. Throughout October and November, observations showed it continuing to maneuver through the star’s layers.
The pulse was manufactured from hot, dense plasma, and initially, it actually made the star brighter within the ultraviolet a part of the spectrum employed by Hubble. Then, around December, the fabric left Betelgeuse behind and entered space. There, it quickly began to chill, forming a dense cloud of dust. In their paper, the authors concluded that, around that point, the dust started blocking the star’s visible light—which triggered that steep drop by brightness that got everybody’s attention. So, it wasn’t an indication that Betelgeuse was on the brink of explosion, and it definitely wasn’t an indication that the energy beings that control our universe had had a glitch—it was just a cloudy few months for this star. Now, no one’s entirely sure where this shade came from within the first place, but the authors speculate that it absolutely was the results of two physical processes lining up just right: For one, the fabric was likely caught in the updraft of what’s called a convection cell.
Convection is that the circular motion of mattering the outer layers of a star that plays a giant part in transporting the star’s heat from its core to the surface. At the identical time, the fabric likely got a lift from the star’s natural expansion. See, Betelgeuse goes through cycles of pulsation on time scales of around a year. It just happened to be expanding in late 2019, so between that and a strong convection updraft, the fabric just may have gotten the oomph it needed to interrupt through the star’s surface and into space. Then, after some months of dimming the star, the cloud seems to own drifted out of our view, or even just dissipated. Either way, we’re seeing Betelgeuse bright and clear again. It’s a subtle story that may are really hard to unsnarl without Hubble’s help, so we’re lucky the telescope just happened to be pointed the proper way at the correct time!
Thanks for reading.