Astronomers have made a decisive step to understanding of the nature of supernova stars of Ia type* in the beginning of this year. Works of the leading research assistant of the RAS Institute of Space Studies, Marat Gilfanov, Dr. Sc. (Phys. & Math.), and his postgraduate student Akosh Bogdan from the Institute of Astrophysics of Max Planck Society (Germany), have shown: the most probable reason of their explosions is a merging of two white dwarfs**. This conclusion is extremely important for cosmology as the rate of the Universe expansion is determined according to such space objects. It was based on the data received with the help of Chandra X-ray orbital observatory of the US National Space Agency, published by Gilfanov and Bogdan in the Nature magazine in February 18, 2010.
Astronomers refer to flashes of supernova Ia type stars as "standard candles"—on the basis of practically identical luminosity. Besides, they are extremely bright, therefore they can be found at great distances, comparable with the size of a part of the Universe under observation. Measuring red displacements of heavenly bodies and distances to them, it is possible to determine its expansion rate at different moments of time in the past. For example, on the basis of such data, in 1998, specialists assumed that there existed a certain mysterious "dark energy"***.
However, up till now the mechanism of flashes has remained unclear. It was practically obvious that supernova Ia type stars are a result of a thermonuclear explosion of the white dwarf. The most probable reason-exceeding a critical limit of the mass equal to ~ 1.4 of the Sun's mass—was also mentioned. For more than 20 years the scientists have been arguing about the way the accumulation of the substance leading to explosion is taking place.
Two scenarios were considered. According to the first one, the white dwarf while interacting with a usual star gradually "draws" to itself the substance of the partner (thi ... Read more