Rare supernova relic found in our galaxy

NASA’s Chandra has discovered the remains of a stellar explosiion at the centre of the Milky Way

Supernovae are stellar explosions that seed the galaxy with the elements vital for life. Sagittarius A East (Sgr A East) is a supernova remnant that lies near Sagittarius A*, the supermassive black hole at the centre of the Milky Way. According to a statement from the Chandra X-ray Observatory, this supernova remnant is the first known example of an unusual type of white dwarf stellar explosion called a Type Iax supernova.

“While we’ve found Type Iax supernovae in other galaxies, we haven’t identified evidence for one in the Milky Way until now,” said Ping Zhou from Nanjing University in China. “This discovery is important for getting a handle of the myriad of ways white dwarfs explode.”

There are different types of stellar explosions, ranging from those triggered by the collapse of massive stars to those that are triggered by smaller white dwarf stars that have pulled too much material from a companion star or collided with another white dwarf.

White dwarf explosions – generally designated as Type Ia supernovae – are an important source of chromium, iron and nickel in the universe. However, using the Chandra observations, astronomers found Sgr A East produced different relative quantities of essential elements and created a less powerful explosion than a typical Type Ia supernova, suggesting it is instead a Type Iax supernova.

“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 Shing-Chi Leung from the California Institute of Technology. “If we’re right about the identity of this supernova’s remains, it would be the nearest known example to Earth.”

“While we’ve found Type Iax in other galaxies, we haven’t identified evidence for one in the Milky Way until now” Ping Zhou