When it comes to capturing the imagination of the non-scientific community, few things do it better than supernovae. What could be more alluring than something larger than our planet collapsing in on itself, causing such a massive implosion that it can be seen from light-years away?
Such events have been witnessed and recorded throughout history, causing ancient astronomers to note the position of the bright new stars in the sky.
A supernova first spotted by ancient Chinese observers in A.D. 185 has now caught the attention of researchers at N.C. State. This dying star, which the Chinese referred to as a “guest star,” lingered in the night sky for eight months.
This supernova, designated RCW 86, is the oldest recorded supernova in history, which fascinates University post-doctoral researcher Brian Williams.
“The historical connection to it makes an object like this more interesting than another might be,” Williams said of RCW 86.
Though astronomers and astrophysicists have long believed RCW 86 to be the mysterious the star that appeared in the sky over China 1,826 years ago, lingering questions remained as they studied the remnants of the supernova that are still visible today through the use of telescopes.
The first issue researchers address is what kind of supernova it is.
“There are two different types of supernovae we know about,” Mary Burkey, a senior in physics, said. Burkey works as the outreach coordinator of the Society of Physics Students. “In a broad classification sense there’s the core collapse…and the other one is a thermo-nuclear reaction.”
Scientists now have conclusive evidence to place the star into the latter grouping of thermo-nuclear reaction, or a “Type Ia” supernova. This type of supernova, according to Williams, is created when a white dwarf star is located near a larger stellar body. The proximity of the white dwarf to the larger star causes it to siphon matter from this larger star, eventually making it unstable and causing the large explosion. In the case of RCW 86, the explosion could be seen on earth without telescopic equipment.
The second question this supernova raised for researchers was the matter of its size. This supernova is 85 light-years in diameter, which is larger than most supernovae that have been observed.
“This must have exploded into a region where there was very little stuff around it,” William said.
This prime positioning would thus allow the outward expanse of the explosion to reach greater limits than would occur if other bodies were in the way of the event.
On a more primal note, supernovae have always seemed to have the ability to capture the public’s imagination. The images provided by X-ray and infrared observations of the these stellar events provide awe inspiring views of the universe not just for those who have dedicated their academic lives to study these supernovae, but for novices and non-physicists as well.
“I took a course on stellar physics my sophomore year,” Alex Milhazes, a senior in criminology, said. “I thought what we learned about supernovae was really interesting, and I found the fact that they’re an implosion rather than an explosion rather intriguing.”
Although Williams is no astronaut or space explorer, his discovery of supernova RCW 86 being a Type Ia star will impact deep space research and has cleared up myths from the past.
