by Astronomers have discovered the first example of an extremely rare type of star system that will one day explode in an “ultra-powerful” gold-producing explosion.
These types of stars destined to become “kilonovae” explosions are so rare that only about 10 such systems are known to exist in the entire Milky Way, scientists at Embry-Riddle Aeronautical University in the US said.
Previous research had shown that these explosions occurred when two extremely small and dense cosmic entities, known as neutron stars, merged.
Researchers describe the recently discovered unusual star system known as CPD-29 2176, located about 11,400 light-years from Earth, in a new study published last week in the journal. Nature.
Using the Smarts 1.5m telescope in Chile, the scientists were able to deduce the orbital characteristics and types of stars that made up this system.
They discovered that this star system was strangely composed of a neutron star and another closely orbiting massive star in the process of becoming an “ultra-stripped supernova” with most of its outer atmosphere stripped away.
“To one day create a kilonova, the other star would also have to explode as an ultranaked supernova so that the two neutron stars could collide and merge,” said study co-author Noel D Richardson of Embry-Riddle Aeronautical University. he explained in a statement.
Studying such systems that are destined to go kilonovae can unravel how such explosions form and also shed light on the origin of the universe’s heaviest elements, such as gold, uranium and thorium, the scientists noted.
“For quite some time, astronomers speculated about the exact conditions that could eventually lead to a kilonova,” said André-Nicolas Chené, another author on the study.
“These new results show that, at least in some cases, two sister neutron stars can merge when one of them was created without a classical supernova explosion,” said Dr. Chene.
While the Milky Way is known to contain at least 100 billion stars, such kilonovae are so rare that the binary system driving them is “essentially a one in ten billion system.”
“Before our study, the estimate was that only one or two of these systems should exist in a spiral galaxy like the Milky Way,” Dr. Chene explained.
However, scientists said the explosion is not imminent.
The massive star could take at least a million years to finish its life and leave behind a second neutron star.
Later, when the two neutron stars eventually merge, the resulting kilonova explosion will produce powerful gravitational waves and leave behind large amounts of heavy elements such as gold and silver, the scientists explained.
