Scientists capture first astounding ‘slow supernova’ which could be unique in our galaxy

Sagittarius A East is the first potential ‘Type Lax’ supernova to be discovered in the Milky Way

Adam Smith@adamndsmith
Thursday 11 March 2021 13:37

Astronomers have managed to capture an image of an astonishing stellar explosion showing the remnants of a supernova.

Located near the centre of the Milky Way, the remnant Sagittarius A East was thought to be the remains of a massive star that exploded - but scientists now have a different theory.

Study from Nasa’s Chandra X-ray Observatory have indicated that the remnants actually come from the explosion of a white dwarf that pulled in material from a companion store before exploding in a flash of light.

Astronomers call this a “Type Ia supernovae”, because they consistently give out the same amount of light anywhere in the universe, but Sagittarius A East is no ordinary Type La.

Instead, it belongs to a slightly weaker version of the supernova called a “Type Lax”, and Sagittarius A East is the first to be discovered in the Milky Way.

“While we’ve found Type Iax supernovae in other galaxies, we haven’t identified evidence for one in the Milky Way until now,” Ping Zhou of Nanjing University in China, who led the new study while at the University of Amsterdam, said.

“This discovery is important for getting a handle of the myriad ways white dwarfs explode.”

White dwarf explosions are vital in the study of the universe, as the heat of a star’s nuclear furnace, or the explosion in its death, is the only place where elements like iron, nickel, and chromium can be created.

“This result shows us the diversity of types and causes of white dwarf explosions, and the different ways that they make these essential elements,” said co-author Shing-Chi Leung of Caltech in Pasadena, California.

“If we’re right about the identity of this supernova’s remains, it would be the nearest known example to Earth.”

The cause of these kinds of phenomena remains up for debate, but scientists believe that the thermonuclear reactions in the star travel much more slowly than others, which leads to weaker explosions.

Previous studies have not ruled out that Sagittarius A East is a normal Type Ia supernova, but this new study conducted argues against both the massive star and the normal Type Ia interpretations; they have been published in The Astrophysical Journal, while a preprint is available online.

“This supernova remnant is in the background of many Chandra images of our galaxy’s supermassive black hole taken over the last 20 years,” said Zhiyuan Li, also of Nanjing University.

“We finally may have worked out what this object is and how it came to be.”

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