An international team of astronomers recorded the most powerful cosmic flare in the history of observations. It took place at the center of a galaxy 2.6 billion light-years from Earth. According to the findings of the researchers, it was generated by the explosion of a large star. This is reported by Science Alert with reference to an article in the journal Nature Astronomy.
The transient (brightness-changing object) PS1-10adi was discovered in 2010 with the Pan-STARRS telescope at the Haleakala Observatory, located at the summit of the volcano on Maui Island in the Hawaiian archipelago. According to astronomers, the flare energy was 2.3 × 1052 erg, which is one to two orders of magnitude higher than the luminosity of ordinary supernovae. PS1-10adi has been extinct for more than three years, all the while remaining brighter than its parent galaxy.
Similar processes are found, as a rule, in Seyfert galaxies - varieties of star clusters with active nuclei (AGN). However, changes in PS1-10adi brightness were not characteristic of the known AGN classes, so the researchers proposed new mechanisms to explain the PS1-10adi occurrence.
The spectrum of the transient was reminiscent of that of type IIn supernovae - explosions of large stars arising from the collapse of a massive core. In the latter case, PS1-10adi should have been a hypergiant with a mass more than a hundred times the mass of the Sun. The reason for the unprecedented brightness could be the interaction of matter from the outer shell of the star, ejected during the explosion, with a very dense interstellar medium.
According to another version, an outbreak could occur if an object of smaller mass came too close to a supermassive black hole in the center of the galaxy and was torn apart by tidal forces. However, the evolution of the luminosity PS1-10adi does not correspond to the picture that is observed in the case of a black hole. The flash was extinguished too slowly, and when destroyed by tidal forces, the luminosity of the transient should have dropped relatively quickly.
In rare cases, the picture of the destruction of a star by a black hole can still resemble a type II supernova, when only a very small fraction (less than one percent) of the star's matter forms an accretion disk. The rest of the matter is thrown away and also interacts with the dense medium.