Massive stars usually end their lives in spectacular supernova explosions, but there are also very few that go out quietly like squibs. Astronomers have recently discovered a rare binary star system with a chance of only 1 in 10 billion that exists, consisting of a neutron star and its companion star that went through a quiet “stripping supernova” phase.
The system, called CPD-29 2176, consists of a neutron star and a larger Be-type star that orbit each other every 50 days in a strange, nearly circular orbit.
Under normal circumstances, a black hole or a neutron star precursor will kick the companion star due to a supernova explosion, and eventually orbit the companion star in a highly elliptical orbit. However, the circular orbit indicates that the neutron star precursor is a massive star, but it has lost most of it before collapsing and exploding. outer mass, so it ends up in the quiet “superstripped supernova” phase, where the explosion isn’t powerful enough to push the companion star away.
▲ The life of CPD-29 2176 binary star system.
The CPD-29 2176 system is now in a strange dynamics. The Be-type companion star has absorbed the partner matter to increase its volume. It has been rotating at a high speed like a top for hundreds of millions of years, so now it starts to lose matter.
The team of Embry-Riddle Aeronautical University in the United States predicts that in the future, the Be-type companion star should also undergo the superstripping supernova stage, and another neutron star will be formed in a million years; In the collision and merger, a kilonova (kilonova) explosion is triggered, the brightness of which is only 1-10% of a typical supernova explosion, and heavy elements such as gold, silver, xenon, and uranium are formed.
The new paper was published in the journal Nature.
(Image credit: Embry-Riddle Aeronautical University)
