Astronomers have seen the first example of an extremely rare type of galaxy destined to one day explode in an “ultra-powerful” gold-producing explosion.
Such types of stars destined to become “kilonova” explosions are so rare that only about 10 such systems are known in the entire Milky Way galaxy, said scientists at Embry-Riddle Aeronautical University in the US.
Previous research had shown that these explosions occurred when two extremely small and dense cosmic entities known as neutron stars merged.
Researchers describe the newly discovered unusual galaxy known as CPD-29 2176 — about 11,400 light-years from Earth — in a new study published last week in the journal Nature.
Using the 1.5 m Smarts telescope in Chile, scientists were able to deduce the orbital characteristics and types of stars that made up this system.
They found that this star system was strangely made of a neutron star and another closely orbiting massive star that was 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 ultra-stripped supernova, so the two neutron stars can eventually collide and merge,” study co-author Noel D Richardson, of Embry-Riddle Aeronautical University , explained in a statement.
Studying such systems destined to go kilonova could unravel how such explosions originate and also shed light on the origin of the heaviest elements in the universe, such as gold, uranium and thorium, scientists stressed.
“For some time astronomers have speculated about the exact conditions that could ultimately lead to a kilonova,” said André-Nicolas Chené, another author of the study.
“These new results show that in some cases two 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 leading to them is “essentially a one-in-ten-billion system.”
“Prior to our study, it was estimated that only one or two such systems should exist in a spiral galaxy such as the Milky Way,” explains Dr. Chen out.
However, scientists said the explosion is not imminent.
It could take at least a million years for the massive star to end its life, leaving behind a second neutron star.
Then, when the two neutron stars finally merge, the resulting kilonova explosion will produce powerful gravitational waves and leave behind large amounts of heavy elements such as gold and silver, scientists explained.