An international team of astronomers recorded the unexplained disappearance of giant stars in the galaxy located 75 million light years from Earth. According to scientists, the sun might shrink into a black hole without turning into a supernova. Article with the results of scientific work published in the journal Monthly Notices of the Royal Astronomical Society.
The researchers observed a bright blue variable in the dwarf galaxy PHL 293B using an array of telescopes VLT (Very Large Telescop) in Chile. The stars in this galaxy is characterized by a low metallicity, i.e., low content of elements heavier than hydrogen and helium. According to the predictions of scientists, some very massive stars with low metallicity could end its life as a bright blue variables, which then drop his weight and become stars wolf-Rayet depleted in hydrogen. However, the life cycle of these stars is studied quite poorly.
Signs of a bright blue variable (LGB) in the galaxy PHL 293B was discovered during observations conducted from 2001 to 2011. Then astronomers have identified in the spectrum of the galaxy series Balmer, which is formed by the transition of electrons from excited levels of hydrogen atoms on the second, while emitted visible and ultraviolet light. Along with the presence of iron oxide (II) and the weak spectral lines of helium is indicated LGB. Although some scholars doubted the existence of the stars, the creators of the work proved that she really was in the galaxy and has actively thrown his lot in 2011.
According to the models of radiation transfer during the 2001-2011 years LGB had a luminosity equal to the luminosity of more than 2.5 million Suns. In the year, the star lost of 0.005-0.02 mass of the Sun, and the velocity of the stellar wind were a thousand kilometers per second.
But then the researchers analyzed the spectral data of 2019, but has not found evidence of a series Balmer. As the authors write in the article, since 2011 bright blue variable could complete the stage of the eruption, reduced the brightness, and thrown dust obscured star. According to alternative explanation, LGB just collapsed into a black hole, bypassing the stage of a supernova. Since the probable mass of the star lies in the range from 85 to 120 solar masses, the resulting black hole must have a mass of 40-90 Suns, or below if LGB was part of a binary system.
Another possibility is a supernova explosion that occurred in the years 1995-1998, when photometric observations were not conducted. In this case, the line Balmer had to be generated in the interaction of a black hole with a dense circumstellar environment.