On average, the Sun rotates on itself once every 27 days, while the Earth does so every 24 hours. But about 2,000 light-years away there is a white dwarf, a ‘vampire star’ It absorbs material from a companion star, which has broken all known records by spinning once every 25 seconds. Which is vastly less than the several hours or days it normally takes for an ‘ordinary’ white dwarf to make one complete rotation. It is, therefore, the fastest stellar rotation ever observed so far. Not counting, of course, such strange objects as neutron stars or black holes. The finding has been published on the Cornell University server
A white dwarf is what remains of a star of less than ten solar masses when it exhausts its nuclear fuel and violently expels its outer layers into space. It is, in fact, one of the stages of stellar evolution. One that, by the way, will pass through the vast majority of stars we know, including the Sun. Not surprisingly, white dwarfs are, along with red dwarfs, the most abundant stars in the entire Universe.
Its name is LAMOST J0240 + 1952, it is part of a binary system (two stars that orbit each other) and it is located in the constellation of Aries. It is about the same size as the Earth, although much denser, which implies that it is almost as massive as the Sun. Its gravitational force is so great that if we were to drop a stone on it from a few meters high, it would crash into the surface at several thousand km per hour.
The ‘fault’ of this rapid rotation is his partner, a much older red dwarf that revolves around him and is being ‘vampirized’ by his little sister. The strong gravity of the white dwarf is, in effect, absorbing material from the other star, and the ‘stolen’ gas that falls on it is making it spin faster and faster, in a way analogous to how falling water spins. the wheel of a mill.
The discovery took place during the night of August 7. It was then that the astronomer Ingrid Pelisoli, from the University of Warwick, together with her colleagues detected a flash of light that was repeated every 24.93 seconds, revealing the very fast rotation of the white dwarf. 5 seconds less, by the way, than the previous stellar rotation record.