In May 2023, Japanese amateur astronomer Kōichi Itagaki made an exciting discovery: he discovered a supernova that was born just hours before his observations. This unusual and early detection allowed astronomers to unravel some of the mysteries of stellar evolution and discover something completely unexpected while observing the exploding star.
The supernova, named SN 2023ixf, is located at a relatively short distance from us, just 20 million light years away in the Pinwheel Galaxy, located in the constellation Ursa Major. This location made it an ideal object for observations in various wavelengths, ranging from visible light to microwave waves. Scientists rarely have this chance to observe the development of a supernova from the very first moments of its birth.
Initial estimates place supernova SN 2023ixf as a Type II, or core-collapse supernova. These supernovae play an important role in the universe because they are sources of important elements and can eventually turn into neutron stars or even black holes. However, the behavior of SN 2023ixf immediately after its discovery turned out to be unusual.
According to standard theory, a star must collapse under its own weight before exploding, and only after that does the explosion occur. However, SN 2023ixf behaved differently - the explosion flash occurred with a significant delay after the start of compression.
Astronomers later found out that the shock wave from the explosion collided with the mass of material ejected by the star, which slowed down its movement. Analysis of the emission of SN 2023ixf in various ranges allowed scientists to reconstruct the chronology of events. It turned out that the red giant, which became the star SN 2023ixf, ejected a mass of material equivalent to the mass of one solar mass a year before it turned into a supernova. This ejected material collided with a shock wave caused by the internal collapse of the star's core and slowed its motion.
Such phenomena, when a star loses mass before exploding, have not been observed before, and SN 2023ixf was a real surprise for astronomers. This also indicates that our knowledge of the evolution of stars leading to type II supernovae is still far from complete. Further observations of SN 2023ixf and the search for similar events could significantly expand our knowledge and help better understand such amazing phenomena in space.