Scientists from the University of Warwick have found an unusual double star in the constellation Gemini, one of the stars in which has turned into a drop under the influence of the gravity of its neighbor.
In the new work, the authors studied an unusual binary system of white dwarfs.
White dwarfs are stars consisting of electron-nuclear plasma, devoid of sources of thermonuclear energy and glowing due to their thermal energy, gradually cooling down over billions of years.
Pelisoli and her colleagues have discovered a double star that will soon merge and explode. Analyzing the data collected by the orbiting telescope TESS, they drew attention to the star HD265435. It is located in the constellation Gemini at a distance of 1.5 thousand light years from Earth.
On the one hand, a white dwarf can absorb enough matter for its neighbor’s plasma to start flowing directly to its surface. If this does not happen, then the stars will gradually approach and merge. And in fact, and in another case, a supernova explosion will occur.
Indgrid Pelisoli, one of the authors of the article and a research fellow at the University of Warwick.
The brightness of this star either increased or decreased, usually this indicates the presence of other planets nearby, but in this case it turned out to be a sign of the unusual structure of this star system.
The change in brightness was due to the fact that HD265435 is a double star. It consists of a white dwarf invisible to us and the so-called hot subdwarf. So scientists call very compact and hot luminaries that arise after the ejection of the outer shells by some types of large stars in the last stages of their existence.
The subdwarf turned out to have an unusual shape, it looked like a drop stretched out under the force of gravity.
In about 70 million years, both stars will merge. As a result, an object will appear at least 1.65 times heavier than the Sun.