Mysterious star reemerged from the dead
ASTRONOMY German astronomers have discovered a very unusual star in the Cassiopeia constellation. It shines 40,000 times more brightly than the Sun from the centre of a star nebula, but there is no indication that the radiation is produced by the fusion of hydrogen and helium, as in other stars. It also ejects charged particles in the form of a solar wind so intense that it should derive from two stars, not one.
According to astronomers from the University of Bonn, the reason may be that this star was indeed once two stars not living, bright stars like our own Sun, but burntout dead stars: white dwarfs.
If the astronomers are correct, the strange star is the result of a very rare phenomenon in which two white dwarfs orbit each other ever more closely, finally meeting and fusing. In such cases, the combined mass is sufficient to revive nuclear processes in the star, not with hydrogen and helium as fuel, but using heavier elements such as oxygen and neon. This causes intense radiation that is emitted not in the visible spectrum, but as infrared light.
This theory can also explain the intense solar wind that is spun away at a speed of 58 million km/h. This would not be possible from a normal white dwarf.
Astronomers consider it quite the stroke of luck to find proof that stars can be reignited in this unusual way, since they estimate that there are only a handful of stars in the Milky Way that have gone through this process, and furthermore they do not live very long. Over a few thousand years such a revived star will exhaust its fuel reserves and then end its new life in a supernova explosion.