In 185 A.D., Chinese astronomers noted a “guest star” that mysteriously appeared in the sky and stayed for about 8 months. By the 1960s, scientists had determined that the mysterious object was the first documented supernova.
Later, they pinpointed RCW 86 as a supernova remnant located about 8,000 light years away. But a puzzle persisted. The star’s spherical remains are larger than expected. If they could be seen in the sky today in infrared light, they’d take up more space than our full moon.
NASA said Monday, that the astronomers using new data from its Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) in combination with existing information from the Space Agency’s Chandra X-Ray Observatory and the European Space Agency’s XMM-Newton Observatory, were able to solve the puzzle.
Their findings revealed that the event was a “Type Ia” supernova, created by the relatively peaceful death of a star like our sun, which then shrank into a dense star called a white dwarf. The white dwarf is thought to have later blown up in a supernova after siphoning matter, or fuel, from a nearby star.
“A white dwarf is like a smoking cinder from a burnt-out fire,” Williams said. “If you pour gasoline on it, it will explode.”
“This supernova remnant got really big, really fast,” said Brian Williams, an astronomer at North Carolina State University and lead author of a new study detailing the telescope’s findings online in the Astrophysical Journal.
“It’s two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we’ve been able to finally pinpoint the cause,” he added.