A new study from the University of Warwick revealed that an exploding white dwarf star blasted out of its orbit with another star that is in a partial supernova and is now traveling across the galaxy. This opens up the possibility that there are many survivors of supernova traveling in the Milky Way but undiscovered.
The researchers published their study in the Monthly Notices of the Royal Astronomical Society. They analyzed a white dwarf star that was previously found to have a unique atmospheric composition. According to their research, the dwarf star may have come from a binary star that survived its supernova explosion sending the two of them flying through the galaxy in different directions.
White dwarfs are the cores that cooled overtime after the red giants have died and shed their outer layers. The majority of them have atmospheres made from hydrogen or helium and sometimes with carbon dioxide or oxygen dredged up from the star's core.
Blast Sends Star Out of Its Orbit
This white dwarf dubbed as SDSS J1240+6710 was discovered in 2015 and seemed to have an unusual mix of oxygen, neon, magnesium, and silicon. The scientists were able to identify carbon, sodium, and aluminum as well in its atmosphere using the Hubble Space Telescope.
These elements are produced in the first thermonuclear reactions of a supernova. However, the iron group elements are missing from its atmosphere. These are typically cooked up from the lighter ones, which make up the defining features of a thermonuclear supernova.
The absence of iron group elements suggests that it only went through a partial supernova before the nuclear burning died out.
The scientists measure the velocity of the white dwarf and found it traveling at 900,000 kilometers per hour. More so, the white dwarf only has a mass of 40% of the sun, which would be consistent with the loss of mass from a partial supernova.
"This star has a chemical composition which is the fingerprint of nuclear burning, a low mass and a very high velocity: all of these facts imply that it must have come from some kind of close binary system and it must have undergone thermonuclear ignition. It would have been a type of supernova, but of a kind that that we haven't seen before," said lead author Professor Boris Gaensicke of the university's Department of Physics.
More White Dwarfs Could Have Survived a Supernova
There is growing evidence that thermonuclear supernova can happen in very different conditions. The explosion that sent SDSSJ1240+6710 to Milky Way has been caught in the act, or else it would have been just another brief flash difficult to decipher.
There is a vast amount of observational effort into finding supernova in the galaxies. This star's discovery proves that different types of white dwarfs survive a supernova under different conditions.
Clearly, the galaxy is a zoo full of stars undiscovered. Studying the survivors of a supernova in Milky Way helps scientists to understand the myriads of a supernova that goes off in the galaxies.
