The star Betelgeuse died out a bit in 2019. Astronomers think they know why: ScienceAlert

The star Betelgeuse visibly muted in 2019. Now, new analysis reveals why: Betelgeuse exploded and is still recovering.

The red supergiant star, which is about 530 light years from Earth, is among the brightest in the night sky. The star forms the shoulder of the constellation Orion (The Hunter).

It’s also geriatric: Betelgeuse is nearing the end of its stellar life and will eventually explode in supernova visible from Earth, although it may take another 100,000 years, according to 2021 research.

At the end of 2019, Betelgeuse’s light began to fade. In February 2020, he had lost two-thirds of its normal brightness seen from Earth.

Scientists studying the strange dimming concluded that the star itself was not about to go supernova imminently, but that a giant dust cloud had obscured some of the star’s light.

Related: Bright star Betelgeuse could harbor a deep, dark secret

Now scientists using the Hubble Space Telescope have revealed that this dust cloud was the result of a huge ejection from the star’s surface: a plume more than 1 million miles (1.6 million kilometers) from diameter may have risen from the star’s interior, producing the equivalent of a starquake, a shock that blew off a portion of the star’s surface 400 million times larger than usually observed in the Sunit is coronal mass ejectionsthe team reported in an article published in the Preprint Database arXiv and accepted by The Astrophysical Journal for publication.

“Betelgeuse continues to do some very unusual things right now; the inside kind of bounces around,” study author Andrea Dupree, associate director of the Harvard & Smithsonian Center for Astrophysics, said in a statement. statement.

This is uncharted territory in star science, Dupree said.

“We’ve never seen a huge mass ejection from a star’s surface before,” she said. “We’re left with something that we don’t fully understand. It’s a totally new phenomenon that we can observe directly and resolve surface detail with Hubble. We’re observing stellar evolution in real time.”

The new research also incorporated information from various other stellar observatories, such as the STELLA robotic observatory in Spain’s Canary Islands and NASA’s Earth-orbiting STEREO-A spacecraft.

By bringing together different types of data, Dupree and his team were able to put together a narrative of the eruption and its aftermath.

The flare blew away part of the star’s lower atmosphere, the photosphere, leaving behind a cool area that was further occluded by the dust cloud from the flare.

Four different images of the gradation of Betelgeus
(NASA, ESA and E. Wheatley (STScI))

Above: In the first two panels, seen in ultraviolet light with the Hubble Space Telescope, a bright, hot bead of plasma is ejected by the emergence of a huge convection cell on the surface of the star. In panel three, the outgoing and expelled gas rapidly expands outward. It cools to form a huge cloud of obscuring dust grains. The last panel reveals the huge dust cloud blocking light (as seen from Earth) from a quarter of the star’s surface.

The piece of photosphere was many times the mass of Earth moonaccording to the NASA press release.

This cool spot and cloud of dust explain why Betelgeuse’s light has faded. The star still feels the reverberations, the researchers found.

Prior to the eruption, Betelgeuse had a pulsating pattern, darkening and brightening over a 400-day cycle. This cycle is now over, at least temporarily.

It’s possible that the convection cells inside the star are still stirring, disrupting this pattern, the researchers found.

According to NASA’s Hubblesite, the star’s outer atmosphere may have returned to normal, but its surface may still shake like Jell-O.

The flare is not proof that Betelgeuse will soon become a supernova, the researchers said, but it does show how old stars are losing mass.

If Betelgeuse eventually dies in a stellar explosion, the light will be visible by day from Earth, but the star is too far away to have any further impacts on our planet.

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This article was originally published by Live Science. Read it original article here.

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