Scientists have now noticed that the star has been releasing stellar winds over the past 20-30 years.
The supernova remnant was named SNR 1181 and the region was studied extensively.
When a Type Iax supernova creates a white dwarf, it releases stellar winds.
Turns out, the dead star is again releasing stellar winds which might be due to material falling on the white dwarf.
We were also able to simultaneously track the time evolution of each shock region, using numerical calculations."
A star was discovered in the Constellation Cassiopeia in 1181 but after 180 days, it vanished for centuries. The supernova made a re-appearance in the year 2021 and astronomers tried to study what had happened. Scientists have now noticed that the star has been releasing stellar winds over the past 20-30 years. They reached the conclusion after running computer simulations while trying to learn more about it.
The supernova was a Type Iax (pronounced One-a-x) which forms when two white dwarfs slam into each other. When the white dwarfs collided, the result should have been the destruction of the two, however, a new type of white dwarf spinning very fast on its axis was formed. The supernova remnant was named SNR 1181 and the region was studied extensively. Two shock regions were found around the object, an old one following the supernova and a more recent one.
When a Type Iax supernova creates a white dwarf, it releases stellar winds. But more recent winds have been identified and scientists have been trying to understand what was causing them. Turns out, the dead star is again releasing stellar winds which might be due to material falling on the white dwarf.
Lead author of the study, Takatoshi Ko, a doctoral student from the Department of Astronomy at the University of Tokyo, said in a statement, “If the wind had started blowing immediately after SNR 1181’s formation, we couldn’t reproduce the observed size of the inner shock region. However, by treating the wind’s onset time as a variable, we succeeded in explaining all of the observed features of SNR 1181 accurately and unravelling the mysterious properties of this high-speed wind. We were also able to simultaneously track the time evolution of each shock region, using numerical calculations."
Supernova in historical texts
The unique supernova finds a mention in several historical texts of Japan, China and Korea. This includes the records of the Genpei War in Japan (1180-85) called the Azuma Kagami. The text about the establishment of the shogunate following the war chronicled several important events of the time. This includes the appearance of a new star in the constellation of Cassiopeia.
The texts reveal that the brightness of this star at one time was similar to Saturn's and was visible to the naked eye for around 180 days, but vanished soon after.
"The remnant of the SN 1181 explosion is now very old, so it is dark and difficult to find,” explained Ko.
