Unraveling the Mystery of Betelgeuse's Great Dimming Phenomenon
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Chapter 1: Introduction to Betelgeuse's Dimming
In late 2019, observers noted a significant decrease in brightness from the well-known red giant star, Betelgeuse, in the night sky. This phenomenon, known as the Great Dimming of Betelgeuse, raised questions among astronomers and enthusiasts alike.
A recent study sheds light on the intriguing causes behind this dimming. It was discovered that the southern hemisphere of Betelgeuse appeared substantially darker than usual, indicating that a dark gas cloud likely formed around the star, obstructing the light reaching Earth.
“Here we report high-angular-resolution observations showing that the southern hemisphere of Betelgeuse was ten times darker than usual in the visible spectrum during its Great Dimming. Observations and modeling support a scenario in which a dust clump formed recently in the vicinity of the star, owing to a local temperature decrease in a cool patch that appeared on the photosphere. The directly imaged brightness variations of Betelgeuse evolved on a timescale of weeks,” researchers reported in Nature.
Section 1.1: The Role of the Very Large Telescope
Using the Very Large Telescope (VLT) array, operated by the European Southern Observatory (ESO), astronomers conducted new observations of Betelgeuse, revealing that the dimming resulted from a dark cloud of dust obscuring the star's red surface. The internal gas of Betelgeuse engages in convection, akin to boiling water, suggesting that a bubble of gas was expelled and subsequently cooled into dust.
New Images Explain Betelgeuse's Dimming Event: A New Study Reveals Why It Became Fainter - YouTube
This video delves into the latest research findings that explain the factors contributing to Betelgeuse's dimming, providing a deeper understanding of this celestial event.
Subsection 1.1.1: Stellar Mass Loss and Implications
The study also highlighted that massive stars, like Betelgeuse, tend to shed a considerable portion of their mass before transitioning into a supernova.
“We still do not know how these stars can lose up to 60% of their mass in the final stages of their life. This has important consequences for their final fate because this mass loss will set the nature of the supernova progenitor,” explained Miguelès in a Behind the Paper article featured in Nature Communities.
As gas in space cooled, it formed dark dust, which obscured the star. For the first time, researchers observed the processes that create "star stuff," which is essential for forming planets and life.
Section 1.2: The Functionality of SPHERE
Surface images of Betelgeuse were captured using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on the VLT, which was initially designed to observe exoplanets. During the Great Dimming, it proved invaluable for studying Betelgeuse's features.
New Vistas in Astronomy: The Great Dimming of Betelgeuse - YouTube
This video explores the groundbreaking observations made during the Great Dimming of Betelgeuse, highlighting the significance of new astronomical technology.
Light from a star is generally non-polarized, but when it reflects off surfaces or dust clouds, it becomes partially polarized. SPHERE’s technique focuses on this polarized light, which allows for clearer imaging of Betelgeuse and its surrounding materials.
Chapter 2: Advanced Observational Techniques
The GRAVITY instrument on the VLT Interferometer also played a key role during Betelgeuse's Great Dimming. By combining light from multiple telescopes, it achieved exceptional resolution, allowing astronomers to measure celestial objects with remarkable precision.
“By combining the light from different VLT telescopes, GRAVITY can achieve the spatial resolution of an equivalent telescope up to 130 meters in diameter when looking in certain directions in the sky,” stated Xavier Haubois, an ESO astronomer at the VLTI. This resolution is equivalent to viewing a one-Euro coin on the Moon from Earth.
Big Red and Its Future
Betelgeuse, a prominent star in the constellation Orion, is easily identifiable and remains a focal point for many skywatchers. The initial dimming in late 2019 sparked speculation about a possible impending supernova, a phenomenon not seen in our galaxy since the 17th Century.
Although its eventual explosion will be spectacular, recent findings suggest that Betelgeuse is still in the helium fusion stage, indicating that it is not on the verge of a supernova just yet.
This study provides further evidence that Betelgeuse is not likely to erupt imminently, allowing us to appreciate its presence in our night sky for the foreseeable future.
James Maynard is the founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat.
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