What is happening with Betelgeuse, which has become one of the brightest stars in the sky in a few days?
About three years ago, Betelgeuse, that remarkable star in the constellation Orion, had mysteriously lost its luminosity. Pretending to an upcoming supernova explosion that never came. And here today, the red supergiant begins, on the contrary, to shine with a thousand lights. But astronomers already have an explanation.
Between the end of 2019 and the beginning of 2020, a star of the constellation d’Orionconstellation d’Orion baptized Betelgeuse had made a lot of talk about her. There brightnessbrightness from red supergiantred supergiant had indeed mysteriously diminished. Almost 25%. THE astronomersastronomers had talked about “Great Obscuration”. Some had then really believed in an imminent supernova explosion. But nothing had finally happened. Yet here today, the star is back on the front of the stage? This time because she has become unusually bright.
Last April, Betelgeuse even peaked, exceeding its typical luminosity by more than 55%! And here it is gone from the 10e at the 7e place of the brightest stars in the sky. So this time, should we prepare to witness the spectacle of a supernova explosion?
Remember that it is indeed fate that awaits the red supergiant. Somewhere between today — or rather the near future of the order of 10,000 years — and the next 100,000 years. But, given the brightness, the colorcolorin size — more than 750 times that of our Star and almost 20 times its massemasse — and the age of Betelgeuse — only some 8 million years compared to the 4.6 billion years of SoleilSoleil –, astronomers estimate that, while it has probably almost exhausted all its hydrogen reserves, the star is only at the beginning of the nuclear fusion process of theheliumhelium. She has to make it carbonecarbone then oxygen. This will then be converted to siliconsilicon and in ferfer. Before the long-awaited supernova explosion.
Still no supernova explosion in sight
So what is happening on the side of Betelgeuse, if this increase in luminosity is not a harbinger of a very soon explosion? Before speculating, it should be remembered that the red supergiant has been experiencing variations in brightness for a long time. According to fairly regular cycles. But it is true that since the mishap that happened to him at the end of 2019, these cycles seem to be disturbed. Thus the recent observations could be part of the continuity of the Great Obscuration.
Researchers from Harvard-Smithsonian Center for Astrophysics (United States) thus explain how the durationduration of a Betelgeuse cycle that was 400 days so far seems to have simply been more than halved since the luminosity dip observed until the beginning of 2020. Because this cycle is the result of the expansion and the contraction of matter inside the star. However, astronomers’ simulations show that the plume that broke away from the red supergiant at the end of 2019 probably came from inside the star. It was he who finally obscured it. Bringing the passage of its cycle of 400 days to about 140 days.
The crazy increase in luminosity that Betelgeuse is currently experiencing would therefore ultimately only be the manifestation of an instability of the upper layers of the red supergiant. And not sure that any of us are still in this world to witness the spectacle of this decidedly mischievous star exploding in a supernova!