mysticism, shadows, urban legends, occultism, magic, evil spirits, hunting for evil spirits, exorcism, folklore, mythology, paranormal news, anomalous, supernatural, ghosts, norfolk survive one full-blown supernova explosion and explode a second time about 50 years after the first explosion, according to an article published in the journal Nature.
RIA Novosti / Alina Polyanina
“This supernova breaks all the rules by which we thought these objects lived. This is the biggest cosmic mystery I've had to solve in decades of observing star explosions,”said Iair Arcavi of the University of California, Santa Barbara, USA.
Life and death in space
Supernovae flare up as a result of the gravitational collapse of massive stars, when the heavy core of the star contracts and creates a rarefaction wave that throws light matter from the outer layers of the star into outer space. As a result, a glowing gas nebula is formed, which continues to expand for some time after the explosion.
Supernovae of the first type are formed by the explosion of a binary system of a white dwarf and a more massive star, while the more common explosions of the second type are caused by the explosion of giant stars. Such an explosion, as scientists previously believed, is an irreversible process, since the star must cease to exist or turn into another type of space object after the outbreak begins.
Two years ago, Arkavi and his colleagues found what they then thought was a completely ordinary type II supernova in the constellation Ursa Major, iPTF14hls, which exploded in one of the neighboring galaxies at a distance of about 400 million light-years from Earth.
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As Arkavi recalls, scientists expected her cocoon of gas and dust to begin to fade about 100 days after the discovery of the outbreak, but this did not happen either six months or even a year after the iPTF14hls was discovered. Moreover, the spectrum, brightness and temperature of supernova remnants did not change in any way for more than 600 days, which is an extremely uncharacteristic phenomenon for the shroud of a deceased star.
The fact is that supernova remnants usually glow under the influence of two different factors - the decay of radioactive elements that arose during a thermonuclear explosion, and a shock wave that compresses and heats up the discarded gaseous envelopes of the star. Both the one and the other factor, as the researchers note, physically cannot make the nebula glow equally brightly for almost two years.
This misbehavior of the supernova puzzled scientists, and they began to study in detail its surroundings and look for photographs of a potential predecessor of this outburst, analyzing archival photographs of the constellation Ursa Major, taken by various ground and orbiting telescopes over the past hundred years.
Dawn of the "living dead"
This search revealed two unusual things that pointed to the potential nature of the mysterious object that gave rise to this anomalous supernova. First, scientists discovered in the vicinity of iPTF14hls traces of another supernova, which exploded about 50-70 years ago and did not lead to the destruction of the star itself.
Secondly, astronomers managed to find photographs of this outbreak on archival photographs of 1954, which proved that the star that gave birth to it is "immortal", since even a supernova explosion could not destroy it. This, according to Arkavi and his colleagues, indicates that iPTF14hls is an exotic and extremely rare object, the so-called pulsating pair-unstable supernova.
It is believed that pair-unstable supernovae appeared in the early stages of the life of the Universe as a result of the explosions of the first stars, entirely consisting of hydrogen and helium. They were much heavier than modern "heavyweight" stars - such luminaries are 200-300 times heavier than our Sun.
The unusual chemical composition of their bowels led to a special scenario of their death. When the early stars ran out of hydrogen, a core of oxygen ions arose in their centers. At a sufficiently high temperature, oxygen atoms begin to absorb photons produced in the nucleus of the "elderly" star and convert them into pairs of electrons and positrons.
Due to this, the total pressure of photons on the matter of the star (the force that balances the gravitational compression of the star) drops sharply, as a result of which the core begins to shrink and heat up even more. This intensifies the reaction of the formation of pairs of particles from photons, as a result of which the star turns into a huge thermonuclear bomb.
This star bomb, as shown by observations of iPTF14hls, does not explode immediately and does so very gradually, in the form of a series of powerful flares resembling type II supernova explosions in strength and characteristics. If this is so, then the "immortal" star can be a real giant, whose mass will be 95-130 times higher than the sun.
It is still impossible to understand whether this is really so - iPTF14hls continues to remain bright even three years after the flash was discovered. Scientists hope that further observations of it and the discovery of other similar objects will reveal the secrets of the survival of such space "living dead".
