Uncommon stays of an explosion found within the heart of the Milky Approach – Watts with it?
From NASA
February 8, 2021
Back to the gallery
Astronomers may have found our galaxy’s first example of an unusual type of star explosion. This discovery, made with NASA’s Chandra X-ray Observatory, helps understand how some stars shatter and colonize the universe with elements critical to life on Earth.
This fascinating object, which is located near the center of the Milky Way, is a supernova remnant called Sagittarius A East, or Sgr A East for short. Based on Chandra data, astronomers previously classified the object as the remains of a massive star that exploded as a supernova, one of many types of exploded stars that scientists have cataloged.
Using prolonged Chandra observations, a team of astronomers has now concluded that the object is what was left of another type of supernova. It is the explosion of a white dwarf, a shrunken star glow of a fuel-poor star like our sun. When a white dwarf pulls too much material from a companion star or merges with another white dwarf, the white dwarf is destroyed, accompanied by a stunning flash of light.
Astronomers use these “Type Ia supernovae” because most of them emit almost the same amount of light every time, regardless of where they are. This allows scientists to accurately measure distances through space and study the expansion of the universe.
However, data from Chandra indicated that Sgr A East was not of a common Type Ia. Instead, it appears to belong to a special group of supernovae that produce different relative amounts of elements than traditional Type Ias and less powerful explosions. This subgroup is known as the “Type Iax”, a potentially important member of the supernova family.
“Although we’ve found Iax-type supernovae in other galaxies, we haven’t yet found any evidence of one in the Milky Way,” said Ping Zhou of Nanjing University in China, who led the new study at the University of Amsterdam. “This discovery is important in order to get a grip on the myriad explosive possibilities of the white dwarfs.”
White dwarf explosions are one of the most important sources in the universe of elements such as iron, nickel and chromium. The only place scientists know that these elements can be created is in the nuclear furnace of stars, or when they explode.
“This finding shows us the variety of types and causes of white dwarf explosions and the different ways they make these essential elements,” said co-author Shing-Chi Leung of Caltech in Pasadena, California. “If we are right about the identity of the remains of this supernova, this would be the closest known example on Earth.”
Astronomers are still debating the cause of type Iax supernova explosions, but the leading theory is that they are thermonuclear reactions that move through the star much more slowly than type Ia supernovae. This relatively slow course of the explosion leads to weaker explosions and thus to different amounts of elements that are created in the explosion. It is also possible that part of the white dwarf is left behind.
Sgr A East is located very close to Sagittarius A *, the supermassive black hole in the center of our Milky Way, and probably cuts the disk of material that surrounds the black hole. The team was able to use Chandra observations targeting the supermassive black hole and the region around it for a total of about 35 days to study Sgr A Ost and find the unusual pattern of elements in the X-ray data . The Chandra results are consistent with computer models predicting a white dwarf that has undergone slow nuclear reactions, making it a strong candidate for an Iax-type supernova remnant.
“This supernova remnant is in the background of many Chandra images of the supermassive black hole in our galaxy taken over the past 20 years,” said Zhiyuan Li, also from Nanjing University. “We may have finally found out what this object is and how it was created.”
In other galaxies, scientists observe that Type Iax supernovae occur at a rate about one-third that of Type Ia supernovae. There have been three confirmed Type Ia supernova remnants and two candidates less than 2,000 years old in the Milky Way. This corresponds to an age when the remains are still relatively light before they later fade. If Sgr A East is less than 2,000 years old and originated from an Iax-type supernova, this study suggests that our galaxy is aligned with respect to the relative number of Iax-type supernovae in other galaxies.
Along with the suggestion that Sgr A East is the remnant of the collapse of a massive star, previous studies have also shown that a normal Type Ia supernova has not been ruled out. The latest study conducted on these deep Chandra data speaks against both the massive star and the normal Type Ia interpretations.
These results were published today in the Astrophysical Journal and a preprint is available online. The other co-authors of the paper are Ken’ichi Nomoto from the University of Tokyo in Japan, Jacco Vink from the University of Amsterdam in the Netherlands, and Yang Chen from the University of Nanjing.
NASA’s Marshall Space Flight Center administers the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge, Massachusetts and flight operations from Burlington, Massachusetts.
Photo credit: Roentgen: NASA / CXC / Nanjing Univ./P. Zhou et al. Radio: NSF / NRAO / VLA
Read more from NASA’s Chandra X-ray Observatory.
For more Chandra images, multimedia content, and related materials, please visit:
http://www.nasa.gov/chandraLast updated: February 8, 2021 Publisher: Lee Mohon
Like this:
Loading…
Comments are closed.