Betelgeuse first came to attention in late 2019, when the star, which shimmers like a red gem in the upper right shoulder of Orion, unexpectedly dimmed. The supergiant star continues to dim in 2020.
Some scientists have speculated that the star would explode in a supernova, and they have been trying to determine what happened to it ever since.
Now, astronomers have analyzed data from the Hubble Space Telescope and other observatories, and they believe the star underwent a massive ejection of surface mass that lost most of its visible surface.
“We’ve never seen a massive mass ejection from the surface of a star before,” said astrophysicist Andrea Dupree of the Center for Astrophysics. “We haven’t fully understood what’s going on.” Harvard and Smithsonian Institution in Cambridge, Massachusetts said in a statement.
“This is a completely new phenomenon that we can directly observe and resolve with Hubble for surface details. We are watching stellar evolution in real time.”
Our Sun regularly experiences coronal mass ejections, in which the star releases part of its outer atmosphere, known as the corona. If this space weather hits Earth, it could have implications for satellite-based communications and power grids.
But the surface mass ejection experienced by Betelgeuse released The mass is 400 billion times that of a typical coronal mass ejection.
life of a star
Observing Betelgeuse and its unusual behavior allows astronomers to observe what happens later in the star’s life.
As Betelgeuse burns fuel at its core, it has expanded to enormous proportions, becoming a red supergiant. The massive star is 1 billion miles (1.6 billion kilometers) across.
Eventually, the star will explode in a supernova, an event that may be briefly visible during the day on Earth. Meanwhile, the star is going through some fiery tempers.
The mass that stars lose when they burn up through nuclear fusion later in life affects their survival, But according to astronomers, even losing a significant amount of surface mass is not a sign that Betelgeuse is ready to explode.
Dupree and other astronomers studied how the star behaved before, during and after the eruption Try to understand what’s going on.
Scientists believe that a convective plume that extends over 1 million miles (1.6 million kilometers) originated inside the star. The shocks and pulsations from the plume trigger the eruption, which peels off a large chunk of the star’s outer shell called the photosphere.
The Betelgeuse photosphere, several times heavier than the moon, was released into space. As the mass cooled, it formed a huge dust cloud that blocked the star’s light when viewed through telescopes on Earth.
Betelgeuse is one of the brightest stars in Earth’s night sky, so its dimming — which lasted for months — passed Observatory and backyard telescope.
recover from explosion
Astronomers have measured Betelgeuse’s rhythm for 200 years. The star’s pulse is essentially a cycle of dimming and brightening that restarts every 400 days. The pulsation has now stopped – a testament to the importance of this eruption.
Dupree believes that the convective cells inside the star that drives the pulsation are still reverberating in the explosion, and compares it to the sloshing of an unbalanced washing machine tub.
Telescope data It has been shown that with Betelgeuse’s slow recovery, the star’s outer layers have returned to normal, but its surface remains elastic as the photosphere rebuilds.
“Betelgeuse is now going on to do some very unusual things,” Dupri said. “It’s a little bouncy inside.”
Astronomers have never seen a star lose so much of its visible surface before, suggesting that surface mass ejections and coronal mass ejections could be two very different things.
Researchers will have more follow-up opportunities by using the James Webb Space Telescope to observe the mass ejected from the star, which may reveal more clues in otherwise invisible infrared light.