The Dark Energy Camera (DECam), a device fabricated by the U.S. Department of Energy, captured an image of RCW 86, the remains of the first recorded supernova. This supernova, named SN 185, was observed by Chinese astronomers in the year 185 as a “guest star.”
Through DECam’s image, astronomers confirmed that RCW 86 is the resulting structure of SN 185, despite previous beliefs that it would take 10,000 years for such a supernova to form the observed structure. The image allowed astronomers to study how the remains of the supernova have evolved over the past 1,800 years.
The estimate of RCW 86’s age, at around 2,000 years, supports the link between RCW 86 and the observed “guest star” from 185.
However, one mystery still remained: how did RCW 86 expand so quickly? The answer was uncovered through X-ray data, which revealed high amounts of iron. This indicates that the blast was caused by a white dwarf star siphoning material from a companion star until it reached a critical mass and exploded. SN 185 would have been a dazzling sight in the night sky.
Source: National Science Foundation