The Great Dimming: Unraveling Betelgeuse’s Peculiar Behavior
Betelgeuse, the bright red star situated within the constellation Orion, has captured the attention of astronomers worldwide due to its unexpected behavior.
In late 2019 and 2020, it exhibited an unprecedented dimming, surpassing its common brightness level. The occasion was dubbed the “great dimming” as Betelgeuse became fainter than Bellatrix, the third brightest star in Orion.
This unusual occurrence sparked speculations about an imminent explosive demise. However, is there any concrete proof to help this idea? And what would be the potential impact of such an explosion right here on Earth?
Variable Stars: Unveiling Betelgeuse’s Brightness Variations
While most stars remain consistently bright, some exhibit fluctuations of their luminosity. These stars, known as variable stars, include notable examples like Mira, discovered as a pulsating star by German pastor David Fabricius in 1596. Mira undergoes regular expansions and contractions, fascinating astronomers with its variability.
Another well-known variable star is Algol, which experiences periodic eclipses by a companion star. Though approximately 30 such variable stars are visible to the naked eye, observing their brightness fluctuations requires keen attention.
Betelgeuse, the seventh brightest star in the sky (excluding the Sun), is the most luminous among variable stars. At times, Betelgeuse shines nearly as brightly as Rigel, the fourth brightest star in Orion.
However, its brightness occasionally diminishes noticeably. This variation in brightness is caused by pulsations similar to those of Mira, although not as significant or regular.
On rare occasions, a star can undergo a transient phase of extreme brightness. These situations characterize supernovas, the place a complete star culminates its life in a robust explosion.
Supernovas can attain a degree of brightness that’s seen even through the daytime, though such occasions have occurred just a few occasions up to now millennium.
Astronomers eagerly await the chance to witness a nearby, brilliant supernova, even though it stays a rarity.
Betelgeuse’s Mysterious Behavior: Shedding Light on the Enigma
While Betelgeuse is a variable star, the significant dimming experienced in 2021 was remarkable. Within a couple of months, it had dimmed by roughly 60%. Eventually, scientists recognized a cloud as the cause of this occurrence.
Stars like Betelgeuse continually expel gas and dust, and a considerable clump of gas throughout the stellar wind, comparable in size to the star itself, obstructed half of its luminosity.
In fact, visual observations of the star revealed the southern half to be missing. This peculiar finding suggests that sure stars, including Betelgeuse, exhibit weather-like phenomena.
Despite this understanding, the current brightening of Betelgeuse, now 50% brighter than its common state, stays unexplained.
However, the prevailing hypothesis means that the same dust cloud responsible for the dimming could be reflecting light from the star towards us, creating the phantasm of elevated brightness.
Although astronomers cannot be sure, they’re thrilled by this improvement. Betelgeuse boasts a mass roughly 15 to 20 times better than that of the Sun, indicating that stars of this magnitude are likely to culminate in a supernova explosion. The star’s purple hue signifies its classification as a red supergiant, implying it’s already nearing the end of its lifespan.
However, the finale of Betelgeuse’s life should be 1,000,000 years away. Stars like Betelgeuse can survive for over 10 million years—a comparatively brief period in the realm of astronomy however an extensive timeframe from our perspective.
Nevertheless, new models have been proposed, suggesting the possibility of a supernova occurring inside a few thousand years, while others estimate the event to be 1.5 million years in the future.
Betelgeuse harbors numerous mysteries yet to be unraveled. Precise determinations of its mass stay elusive, and even its distance is subject to debate.
Some scientists hypothesize that the star recently merged with a smaller companion, potentially explaining its faster-than-expected rotation. Typically, large stars rotate at a slower pace.
Ancient manuscripts describe Betelgeuse as resembling yellowish Saturn, rather than the reddish Mars it appears as today. Could this alteration in color signify accelerated evolution, suggesting a more imminent supernova?
The Dynamics of a Potential Explosion
If Betelgeuse were to undergo a supernova explosion, what would be the observable effects? Located approximately 500 light years away, the initial indication can be the detection of neutrinos, massless particles, which would be harmless to us. Subsequently, the star would rapidly increase in brightness.
Within one or two weeks, Betelgeuse would shine as brightly as the Full Moon. Over the following months, its luminosity would gradually fade, but it would remain seen in daylight for six to 12 months.
During the night, it would be observable to the bare eye for an additional 1 to 2 years. However, after this era, Betelgeuse would vanish from our sight forever, leaving Orion devoid of its iconic red sparkle.
Is there any potential danger posed to Earth? Supernovas generate high-energy particles called cosmic rays, able to bypassing the Earth’s magnetic area. However, the quantity of radiation received from most supernovas, besides these in shut proximity, can be minimal compared to other forms of radiation.
Furthermore, a supernova explosion ends in the creation of radioactive iron. In reality, traces of this substance have been found in Earth’s seabed and on the Moon, believed to have originated from a supernova explosion that occurred between 2 and 3 million years ago, roughly 300 light years away from us. Although closer than Betelgeuse, this event didn’t pose important threats to life on Earth.
A supernova occurring in shut proximity, inside 30 light years, may certainly current extreme challenges. The ensuing cosmic rays may result in ozone depletion and hazardous ranges of ultraviolet radiation reaching the Earth’s floor.
Ozone depletion by half over a number of hundred to 1000’s of years can be classified as an extinction-level occasion. However, such a closely located supernova would be exceptionally rare, possibly transpiring solely as soon as per billion years.
Ultimately, Betelgeuse could continue to grace our skies for an extended period, offering a fascinating and enigmatic spectacle. There is still a lot to be realized from this extraordinary star, fascinating scientists and stargazers alike.