Scientists at Florida State University (USA) have recorded for the first time an unusual supernova LSQ14fmg, which has unique properties: it slowly flares up and breaks brightness records among supernovae of its class. This is reported in an article published in The Astrophysical Journal.
The researchers analyzed data from telescopes in Chile and Spain. It turned out that a type Ia supernova (white dwarf explosion) caused the surrounding cosmic material to emit strong radiation, indicating the radioactive decay of nickel and the formation of carbon monoxide. This allowed the experts to assume that they observed an explosion of a star, which belongs to the asymptotic giant branch (AGB), turning into a planetary nebula.
The explosion was caused by the merger of the core of the giant AGB and the white dwarf orbiting it. The central star lost a significant amount of mass due to stellar winds before the loss of mass suddenly ceased, and a ring of stellar matter was formed, often seen in planetary nebulae. The supernova shockwave collided with the ring, resulting in a slow increase in brightness.
According to scientists, they received the first convincing evidence that a Type Ia supernova could explode in a system of giant stars on the way to becoming planetary nebulae, which is an important step in understanding the origin of this class of supernovae.
