Recently, astronomers detected a very strange white dwarf as it spins two times per second with a rotation period of approximately 29 seconds per revolution while sucking in materials from its nearby companion. As a matter of fact, it is the fastest spinning white dwarf that has ever been found.
White dwarfs are the core remnants of collapsed sun-like stars. Their oxygen and carbon masses are normally very close to that of our sun although they are quite a bit smaller (approximately the size of Earth). It takes white dwarfs billions of years to emit all of the residual heat into space and it takes millions of years to become cold enough to appear invisible as a black dwarf.
Artist’s interpretation of a white dwarf sucking materials from a minor planet.
The binary system is called CTCV J2056-3014 or J2056 and it is located approximately 850 light-years from Earth. White dwarfs contain tons of charge particles and when they spin, the particles create magnetic fields that stretch outwards, ultimately affecting anything close to them and causing materials from other celestial bodies to be sucked onto the white dwarf’s surface.
If the magnetic fields are weak, the hydrogen that’s being sucked from its companion turns into a normal disk of matter that goes onto the white dwarf. If they are strong, the gas from its companion wraps around the white dwarf and hits the poles, causing a type of aurora borealis. Now, if the magnetic fields are in the middle (not too strong or weak), they are considered to be “intermediate polar” which means that they aren’t strong enough to totally disturb the accretion disk but are strong enough to suck in the gas of its companion. This makes the white dwarf flare and flicker in a manner that is highly unpredictable.
Since J2056 is an “intermediate polar” system, the white dwarf has trouble collecting the gas from its companion onto its surface. Its companion completes a full orbit around the white dwarf in just 1.76 hours. Another strange fact about J2056 is that it doesn’t release much X-ray radiation which is quite unusual for that type of system.
Artist’s interpretation of debris around a white dwarf.
As for the reason why the white dwarf spins so fast, it may be because of its magnetic fields sucking material onto its surface, therefore, making it spin at incredibly fast speeds. And since its magnetic fields aren’t strong enough to slow it down, it keeps spinning. The study can be read in full here.
It’s still unclear whether J2056 is just a very unusual white dwarf or if it in fact represents a new type of cataclysmic variable stars. Whatever it may be, it is very interesting and the information gathered from its unusual characteristics will surely help experts in studying how white dwarfs and their magnetic fields work.
from Mysterious Universe https://ift.tt/3jrDpcN
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