CTIO/NOIRLab/DOE/NSF
In early December 185 A.D., Chinese astronomers recorded a bright “guest star” in the night sky that shone for eight months in the direction of Alpha Centauri before fading out — likely Closest recorded supernova in the historical record. the photo above It gives us a rare glimpse into the whole torn remains From that explosion that happened so long ago, I also captured it Dark energy camera (DECam), mounted on a four-meter telescope at the Cerro Tololo Pan-American Observatory in the Andes Mountains of Chile. DECam has been in operation since 2012, and while it was originally designed to be part of an ongoing business Dark Energy Survey, which is also available for other astronomers to use in their research. This new, broad view of the SN 185 remnant should help astronomers learn more about stellar evolution.
As we wrote earlier, there are two types of known supernovae, depending on the mass of the parent star. An iron core supernova explosion huge stars (greater than 10 solar masses), which collapse so hard that it causes a massive and catastrophic explosion. The temperatures and pressures get so high that the carbon in the star’s core fuses. This stops the collapse of the nucleus, at least temporarily, and this process continues, over and over, with progressively heavier atomic nuclei. When the fuel finally runs out, the iron core (by then) collapses into a black hole or neutron star.
Then there is a Type Ia supernova. Smaller stars (up to about eight solar masses) gradually cool into dense cores of ash known as white dwarfs. If a white dwarf that has run out of nuclear fuel is part of a binary system, it can siphon matter from its partner, adding mass until its core reaches temperatures high enough for carbon fusion to occur. These are the brightest supernovae, and they also shine with remarkably consistent peak brightness, which makes them invaluable.”Standard candles“For astronomers to determine cosmic distances.
There are precious few details about the SN185 available at Later Han book, other than “the size of the bamboo mat” and “the display of various colors, pleasing or otherwise.” Astronomers suspected a possible connection between SN 185 and the remnant structure, which has been dubbed RCW86For a long time, however, they assumed that the event that formed RCW 86 was a core collapse supernova, which would require about 10,000 years for the remaining structure to achieve its current shape.
In 2006, new X-ray data collected by the European Space Agency’s XMM-Newton Observatory and NASA’s Chandra X-Ray Observatory showed that RCW 86 is much younger than previously thought: about 2,000 years old. The authors were able to calculate how quickly the shock wave expanded within RCW 86. They found that there are denser regions where the shock wave expands more slowly, misleading astronomers into thinking the remnant was older than it is. But there are other regions where the shockwave is still inside the bubble—and still expanding rapidly—that provide a more accurate estimate of RCW 86’s age.
The new age estimate significantly strengthened the case that RCW 86 is the remnant of SN 185. In this case, SN 185 may have been a Type Ia supernova, a conclusion based in part on the discovery of a significant amount of iron in the remnant. A white dwarf star devouring its partner in a binary system produces high-speed winds that push gas and dust out and create a cavity before the white dwarf explodes. This enabled all of this debris to expand outwards very quickly to create the impressive ruptured structure that exists today.