The star N6946-BH1, which has been observed by American astronomers for several years, suddenly disappeared. A related study was published in the Monthly Notices of the Royal Astronomical Society and is briefly reported by NASA.
Experts do not know the exact reasons why the luminary N6946-BH1 disappeared from sight. The most likely hypothesis is its gravitational collapse - turning into a black hole. Scientists, having previously observed the star, did not anticipate such a development of the situation - they believed that N6946-BH1 would explode as a supernova.
Observations of the star were carried out using three telescopes - one ground-based LBT (Large Binocular Telescope) and two space ones - Hubble and Spitzer. Luminary N6946-BH1 was 25 times heavier than the Sun and was located at a distance of 22 million light years from Earth in the spiral galaxy NGC 6946.
In 2007, the star experienced a bright flash, which usually indicates its imminent explosion as a supernova. In 2009, a less bright flash was recorded, since then the radiation of the star began to decrease. In 2015, astronomers at the site of N6946-BH1 discovered only a source of infrared radiation (likely produced by matter falling on a black hole). At the same time, there were suspicions that the star had turned into a black hole, this data has been verified only to date.