Thanks to the Chandra X-ray Space Telescope, astronomers have discovered a star that survived after the star was absorbed by the other.
This binary star system, which is officially called the V471 Tauri, in the constellation Taurus. It is composed of a normal star similar to our Sun, and of a small star, which belongs to a class of white dwarfs. The distance between the two stars that orbit a common center of gravity is very low: it is 30 times smaller than the radius of the orbit of Mercury — the closest planet to the Sun.
Studies binary star V471 Tauri with the Chandra telescope have shown that in the upper layers of the atmosphere hot "normal" star has a deficit of carbon atoms relative to nitrogen atoms. It is proof that sometime in the past "normal" star was absorbed in his companion. The star, who is now a white dwarf, was once a major star quite a few times the mass of our Sun. Within a few billion years during nuclear fusion reactions in the core of the star passed conversion of carbon atoms in the nitrogen atoms. When that Coke was over, the star's core contracted and began other nuclear reactions, causing the star expanded and turned into a red giant.
Matter of the core of a red giant, where there was a shortage of carbon, mixed up with material from the outer parts of the star, so its atmosphere is a shortage of carbon atoms compared with their content in a sun-like stars.
Theoretical calculations of the behavior of the system of two stars indicate that when he was a red giant star that has devoured her companion and had a significant impact on its evolution. But when the upper shell of a red giant has been reset, the star-neighbor again was set free, while taking in the former red giant about 10% of its own weight.
In the future, these stars can be swapped. Normal sun-like star after burning the entire nuclear fuel expands and casts of his material on the white dwarf, and if this will matter a lot, the white dwarf can explode as a supernova.
Text: E. Volynkina