NASA's Hubble Space Telescope sees red supergiant star Betelgeuse slowly recovering after blowing its top

Data from the Hubble Space Telescope and other observatories led scientists to the conclusion that the bright red supergiant star Betelgeuse "blew its top" in 2019, shedding a significant amount of its visible surface and releasing a massive Surface Mass Ejection (SME). To my knowledge, this has never happened before with a typical star.

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Coronal Mass Ejections occur often when the sun expels chunks of its outer atmosphere, the corona. While most CMEs are quite small in comparison, the one from Betelgeuse ejected 400 billion times  as much mass.

Monster star is still getting back to normal after the devastating disruption."Betelgeuse continues doing some very unusual things right now; the interior is sort of bouncing," said Andrea Dupree of the Center for Astrophysics | Harvard & Smithsonian.

The new data shed light on the process by which red stars shed mass when their nuclear fusion furnaces run out and eventually explode as supernovae. Their eventual destiny is very dependent to the degree of mass loss. Betelgeuse's unusually spoiled behaviour is not, however, a sign that the star is poised to go supernova in the near future. That mass loss event may not be a precursor to an explosion.

Dupree is now piecing together the star's petulant conduct before, during, and during the eruption into a cohesive account of a never-before-seen gigantic convulsion in an old star.

The STELLA robotic observatory, the Tillinghast Reflector Echelle Spectrograph (TRES) at the Fred L. Whipple Observatory, NASA's Solar Terrestrial Relations Observatory (STEREO-A) spacecraft, NASA's Hubble Space Telescope, and the American Association of Variable Star Observers have all contributed new spectroscopic and imaging data (AAVSO). To Dupree's point, the Hubble data was crucial in unravelling the enigma.

"We've never before seen a huge mass ejection of the surface of a star,” she said. “We are left with something going on that we don't completely understand. It's a totally new phenomenon that we can observe directly and resolve surface details with Hubble. We're watching stellar evolution in real time."

The 2019 titanic outburst may have been triggered by a massive convective plume, with a diameter of over a million miles, rising from the star's interior. The cooling component of the photosphere caused shocks and pulsations, which blew off the chunk of the photosphere, leaving the star with a massive cold surface area beneath the dust cloud. The injury has hampered Betelgeuse's recovery efforts.

A fragment of the photosphere, weighing many times as much as our moon, flew out into space, where it cooled to create a dust cloud that obscured the star from Earth. Even from a backyard, the fading that started in late 2019 and lasted for a few months was immediately apparent. Betelgeuse is one of the brightest stars in the sky and may be seen in the right shoulder of the constellation Orion.

What's more incredible is that the supergiant's previously observed 400-day pulsation rate seems to have stopped, at least temporarily. For over two centuries, astronomers have tracked this pattern in the brightening and shifting of Betelgeuse's surface. The severity of the explosion is shown by the havoc it causes.

In order to explain the star's regular pulsating, Dupree proposes that the star's internal convection cells are sloshing about like an unbalanced washing machine tub. According to TRES and Hubble spectra, the photosphere may be repairing itself, but the surface is still bouncing like a dish of gelatin cake.

Small chunks of the Sun's outer atmosphere are blown off during coronal mass ejections, but scientists have never seen such a big portion of a star's visible surface blasted into space. As a result, it's possible that coronal mass ejections and surface mass ejections are two separate phenomena.

If Betelgeuse were to take the place of the sun as the solar system's primary star, its outer surface would now reach beyond Jupiter's orbit. It wasn't until 1996 that Dupree was able to utilise Hubble to make out hot patches on the star's surface. For the first time, a star other than the sun was captured in its entirety on film.

The James Webb Space Telescope, a NASA telescope, may be able to detect the ejected debris in infrared light as it continues to move away from the star.