Scientists have studied the system RX J0648.0-4418. It consists of a main-sequence star and a white dwarf, which rotates rapidly and absorbs the matter of its companion. Scientists have found that this interesting object is highly compressed and may soon explode as a supernova.

Amazing system
RX J0648.0-4418 is an amazing star system that is 1,700 light-years away from us. Until 1997, it was known as the common star HD 49798. However, it was then found to have X-rays, and it has been scrutinized ever since. New research has found that it could erupt as a supernova after some time.
In 2009, using the orbiting telescope XMM-Newton, scientists found that the cause of X-ray radiation is a white dwarf with a mass 1.2 times greater than the solar mass. It, together with a main-sequence star, forms such a close pair that matter from the latter flows onto it and forms an accretion disk.
There are no other main-sequence stars visible in the optical spectrum that would be sources of X-ray radiation near the Sun. Therefore, scientists have been observing the white dwarf for many years now, trying to unravel its mysteries.
Vampire star
Like all white dwarfs, RX J0648.0-4418 was also once a main-sequence star. It exhausted its hydrogen fuel, went through a red giant stage, and eventually became a tiny and extremely dense clump of hot gas.
White dwarfs are generally considered dead stars because they don’t have thermonuclear reactions. However, if another luminary is nearby, they can turn into a true vampire star. They begin to “feed” on its substance and show a variety of activity.
Among other white dwarfs, RX J0648.0-4418 stands out for its record-low rotation period. It is only 13 seconds, which is really quite short for an object the size of the Earth. Its closest competitor, the white dwarf LAMOST J0240+1952, does it in 25 seconds.
Scientists have long wondered how this white dwarf could have gotten such an incredible spin rate. Because the momentum from the matter falling on it is clearly not enough for that. In addition, this is the only known system in which the white dwarf is partnered with a subdwarf that has had its outer layers ripped off and turned into a helium star.
New research
And now there’s a new batch of research. Scientists have estimated the accretion rate of material on the star and concluded that it really should be spinning it out. And the key role is not the fall itself, but the angular momentum that the gas transmits to the white dwarf.
Due to its extremely high rotational speed, the white dwarf is shrinking. Despite the high rate of absorption of the substance, its diameter decreases rather than increases. And that’s not all. RX J0648.0-4418 is one of the heaviest known white dwarfs, and the fact that it keeps getting more massive means only one thing: after a while, it should explode as a supernova.
Scientists say we are extremely lucky to observe RX J0648.0-4418 at a time when it is just approaching the Chandrasekhar limit. The Earth is not threatened by this outbreak, but it was very interesting to understand what processes lead to explosions.
According to www.space.com