Astronomers have discovered a white dwarf who survived a supernova explosion. Such dwarfs have unusual characteristics and behavior compared to standard stars.
When a big star exhausts all nuclear fuel, it can shed its outer layers of matter and shrink into a hot, wrinkled celestial body called a white dwarf. In the end, when gravity continues to compress the star’s dying core, it can collapse — explode into a supernova — and leave behind a superdense neutron star or black hole.
The authors of the new study discovered an unusual star named LP 40-365. This is a white dwarf that moves incredibly fast to the edge of the galaxy. Scientists consider him to be a “partially burnt remnant of flight”, suggesting that this star managed to survive a supernova explosion and stay alive. True, it should be said that the explosion was not so powerful – according to astronomers, its strength was even lower than the average. Such explosions are called type Ia cricket bombs.
Oddly enough, this unusual star is not an isolated case. Using data from the Gaia Space Telescope of the European Space Agency, the authors of the study also found three additional stars in other parts of the Galaxy with properties and trajectories similar to LP 40-365.
Researchers say that these four strange stars may represent a new type of fate for white dwarfs, who are running out of fuel. They explode and remain charred, shrunken and sweeping across the galaxy at incredible speeds, but still largely intact.
Such partially burned dwarfs form a special class of “runaway” stars, according to the authors of the study, and can shed light on the complex factors that cause stars to explode. But scientists have yet to figure out the mechanism of such a transformation.