As Sun-like stars die in the red giant stage, they gradually shed their outer layers and expose their central core – a white-hot ball of carbon and oxygen. Such a core is similar in size to Earth, but its mass is still similar to that of the Sun.
It is worth mentioning here that, contrary to appearances, most stars appear in pairs, not singly like the Sun. As one star slowly ends its life, the other still hovers around it. Over time, the second star in the system goes through the next stages of evolution and ends the same, or gradually spiraled towards the white dwarf.
When dealing with the latter scenario, matter from the accompanying star gradually tears away from it and falls onto the white dwarf. When a dwarf attracts enough matter to itself, the so-called a new explosion.
The magnetic field always does the job
Recently, researchers have noticed a fairly unique chip that has been cataloged under the unlikely CTCV number J2056-3014. It is located approximately 850 light-years from Earth.
White dwarfs are full of electrically charged particles (like most objects in the universe). They are also relatively small and spin relatively quickly. Rapidly spinning charged particles generate a magnetic field that extends far beyond the surface of the white dwarf and affects how material from the accompanying star sinks to its surface.
If the magnetic field of the white dwarf is weak, the hydrogen from its companion forms a regular accretion disk that gradually falls to the surface of the white dwarf. If, on the other hand, the magnetic field is strong, then it directs matter into streams that wind around the white dwarf and hit its poles.
In the case of J2056, we are dealing with an intermediate stage that allows the formation of an accretion disk, but is also able to pull matter in the immediate vicinity of the star as far as the poles of the dwarf. Thus, the magnetic field prevents the gas from flowing regularly, uniformly and the white dwarf blinks and flashes irregularly and completely unpredictably.
J2056 – an unusual case
The recently discovered white dwarf has a magnetic field that allows an accretion disk to form around it, but at the same time it has difficulty reaching the dwarf’s surface. According to the authors of the study, this particular white dwarf is able to collect the equivalent of the mass of the Earth’s atmosphere in a year, which is extremely low.
As if that were not enough, J2056 does not emit too much X-ray and rotates around its axis. It is de facto the fastest rotating white dwarf – it takes 29 seconds to fully rotate around its axis.
How did J2056 accelerate like this? Perhaps the configuration of its magnetic fields is such that it is able to pull matter to its surface in short jets that accelerate its rate of rotation, and at the same time its magnetic field is weak enough that it is unable to slow down the rotation by electromagnetic interactions with the surrounding area. dwarf accretion disc.
Even so, its low brightness in the X-ray range and the surprisingly fast orbital period of its companion star remain to be explained (the two objects orbit each other in just 1.76 hours).
Quite possibly J2056 belongs to an entirely new class of cataclysmic variable stars. Understanding how it works can significantly improve our understanding of the magnetic fields surrounding white dwarfs. Such knowledge, in turn, can tell us a lot about how such remnants of sun-like stars are formed and how they live.
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The mass of the sun, the size of the earth, and two revolutions per second. Here is the fastest spinning white dwarf