New infrared observations from NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE, reveal how the first supernova, known as RCW 86, ever recorded occurred and how its shattered remains ultimately spread out to great distances. The findings show that the stellar explosion took place in a hollowed-out cavity, allowing material expelled by the star to travel much faster and farther than it would have otherwise. According to Brian J. Williams, an astronomer at North Carolina State University in Raleigh this supernova remnant got really big, really fast. It’s two to three times bigger than would expect for a supernova that was witnessed exploding nearly 2,000 years ago.
The ancient supernova, is located about 8,000 light-years from Earth. With the help new data from Spitzer and WISE and also with existing information from NASA’s Chandra X-Ray Observatory and the European Space Agency’s XMM-Newton Observatory, astronomers were able to find that RCW 86 is a so-called Type Ia supernova, triggered by the relatively peaceful death of a star similar to our sun. This star shrank into a dense star called a white dwarf before siphoning matter, or fuel, from a nearby companion star. The study showed for the first time that a white dwarf can create a cavity like empty region of space around itself before exploding in a Type Ia supernova event. According to researchers the presence of a cavity would explain why the remnants of RCW 86 are so big. Using Spitzer and WISE, the researchers measured the temperature of the dust making up the RCW 86 remnant at about minus 325 degrees Fahrenheit, or minus 200 degrees Celsius. They then calculated how much gas must be present within the remnant to heat the dust to those temperatures. The results point to a low-density environment for much of the life of the remnant, essentially a cavity.