2023-06-10 10:26:26
Betelgeuse, the 10th brightest star in the night sky, continues to fool astronomers. This time it became 50% brighter.
Header image: the red supergiant star Betelgueuse imaged by the Atacama Large Millimeter Array in 2020. (ESO /NAOJ /NRAO / E. O’Gorman/ P. Kervella)
This increase in brightness has some wondering if we are regarding to witness the supernova of Betelgeuse. Fortunately, regarding 724 light-years from Earth, we would not be affected, but we would be able to see the awesome flash caused by such an event.
In recent years, Betelgeuse has become darker and brighter. In 2019, the star lost regarding a third of its usual luminosity.
Comparison of Betelgeuse from January to December 2019. (ESO/M. Montargès et Coll.)
Observations accidentally captured by the weather satellite Himawari-8 suggest that the “Great Dimming” was caused by a combination of cooling from the star and condensation from a nearby dust cloud.
This illustration shows the likely causes of Betelgeuse’s dimming in 2019. (NASA/ ESA/ E. Wheatley (STScI))
This red supergiant is the second brightest star in the constellation d’Orion. This is also called a semi-regular variable star pulsating. This means that its brightness changes roughly periodically. Betelgeuse has a brightness change cycle of 400 days. She also has a 125 day cycle, a 230 day cycle and a 2200 day cycle.
Images from a previous study featuring the supergiant star Betelgeuse taken at different times, showing its evolution during its dimming event. (ESO/ M. Montargès et al.)
The star is nearing the end of its life. It is believed that 8 to 8.5 million years ago, Betelgeuse left the main sequence stars and it became a red supergiant. This means that the star has used up all of its hydrogen fuel, fusing it into helium, causing the star to expand and cool. The fusion of helium into heavier elements, such as carbon, will result in the production of even heavier elements and the explosion of a supernova.
Some astronomers believe the star is in the later stages of this process. But we don’t know how long he has left to live. Even determining Betelgeuse’s evolutionary stage is unclear, and some astronomers suggest it hasn’t even finished burning its helium. A study, submitted to a peer review, looking at the star’s recent increase in brightness (link below) suggests a number of possibilities to explain the star’s increased visibility. One of them is that Betelgeuse might turn into a supernova within 10 years. But this is not the only possibility.
The researchers write in their study:
In fact, it is not possible to determine the exact stage of evolution, since surface conditions hardly change in the late phase near carbon depletion and beyond.
Despite the uncertainty surrounding the exact date, one thing is certain: Betelgeuse will turn into a supernova, one day or another. And when it does, it will light up the night sky.
The brightest supernova in history, known today as SN 1006, occurred in the year 1006 CE and it was visible for months. Some scientists and historians believe the supernova was so bright that people living more than a thousand years ago might read under its light.
Benedictine monks from Switzerland have spoken of a star “sparkling in appearance and dazzling to the eyes, causing anxiety”. Egyptian physician and astronomer Ali ibn Ridwan wrote that “the sky was shining” and calculated that the supernova was three times brighter than Venus. Modern astronomers estimate that the star exploded regarding 7,200 light-years away.
The last supernova to occur in the Milky Way was listed by the German astronomer Johannes Kepler in 1604. It lasted several weeks. Known today as SN 1604 or “Kepler’s supernova” and described in Kepler’s book Stella Novathe star became brighter than Jupiter and Mars at its peak.
When Betelgeuse explodes, astronomers believe the supernova might be as bright as the sun.
The study available in pre-publication in arXiv : The evolutionary stage of Betelgeuse inferred from its pulsation periods.
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