Using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton satellite, astronomers identified a possible remnant of ancient stellar explosion just a few dozen light-years from Sagittarius A*, a supermassive black hole at the center of our Milky Way Galaxy.
This composite image contains X-rays from Chandra and XMM-Newton missions (shown in blue) as well as radio data from the MeerKAT telescope (shown in red) in South Africa. These have been combined with an optical image from the Pan-STARRS telescopes in Hawai’i (red, green, and blue). Image credit: NASA / CXC / UCLA / Zhu et al. / ESA / XMM-Newton / PanSTARRS / MeerKAT / CSA / STScI / SAO / L. Frattare & P. Edmonds.
The evidence for the new supernova remnant candidate, which is located approximately 26,000 light-years from Earth, comes from X-ray data collected by Chandra and XMM-Newton missions.
“The X-ray data reveals a ‘blob’ of X-ray emission that may come from the remains of a massive star that self-destructed as a supernova, buried within the larger cloud of expanding gas,” the astronomers said in a statement.
“It is in a bubble of gas that has had electrons stripped away from hydrogen — called an HII region — surrounding a massive, young star.”
“This bubble is a bright source of radio emission called Sagittarius C.”
“If this is indeed a supernova remnant, then it is expanding at about 3.2 million km per hour (2 million mph) and is at least about 1,700 years old.”
Previously, observations with NASA’s SOFIA mission had shown evidence for an expanding shell of gas surrounding Sagittarius C.
This gave the astronomers a hint that a stellar explosion had occurred in the same spot.
“The long filaments seen in the radio image are caused by energetic particles travelling along magnetic fields that are mostly directed perpendicular to the plane of the Galaxy,” they said.
“The nuclear fusion engines of stars create elements from hydrogen and helium that were abundant at the beginning of the Universe.”
“When stars explode at the end of their lives as supernovae, they send these newly synthesized elements into interstellar space and provide material for the next generation of stars and planets.”
The researchers searched the X-ray data for signs of increased amounts of key elements in the remnant, which would have been caused by the stellar explosion blasting them into space.
While they did not see an enhancement, this could imply that the stellar debris has already mixed with the surrounding gas.
An alternative explanation for the X-ray blob is that the hot gas comes from a collection of massive stars in the region.
“We do not think this explanation is likely, because the X-ray emission from the blob is more than ten times brighter than the X-ray emission of large, known stellar clusters with bright, massive stars,” the scientists said.
Their paper was published April 16 in the Astrophysical Journal.
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Zhenlin Zhu et al. 2026. Diffuse X-Ray Emission in the Sagittarius C Complex. ApJ 1001, 197; doi: 10.3847/1538-4357/ae547c
