It is a wonder looking up at space, seeing the continuum of the cosmos in beautiful celestial bodies exploding, reforming, and shining brightly in the night sky.
In this stellar life cycle, scientists have discovered the brilliant birth of a new star created from the collision of two dying ones.
Two white dwarfs collide
Researchers found that the luminous new giant was made by the collision of two diminishing white dwarfs. One of them was full of helium, and the other had plenty of oxygen and carbon. After orbiting each other for a long time, the helium-rich dwarf consumed its neighbor, splashing itself with oxygen and carbon.
The result was now massive enough to restart the nuclear fusion and bring to life a stunning new star with a helium core and a coating of oxygen and carbon.
A rare stellar find
This new star, this astrological tootsie pop, is such a space marvel because normally it should be the other way around: with the helium on the outside and the oxygen and carbon on the inside.
The oxygen-carbon rich white dwarf would typically be covered with the helium one because oxygen and carbon are heavier than helium. What must’ve happened for this new start to occur was that its two parents would orbit each other for just the right amount of time, delicately exchanging material at the right rate, for the helium heavy star to become more massive than its oxygen-carbon partner.
“That [combination] has never been seen before,” says study coauthor Nicole Reindl, an astrophysicist from the University of Potsdam in Germany. “That tells you the star must have evolved differently.”
To test this, the team from the Max Planck Institute for Astrophysics in Garching, Germany, ran a simulation and learned that the theory of the new star’s formation is correct. It’s the first of its kind to be discovered.