Rare pair of neutron stars destined for explosion may reveal how heavy elements form in Universe, study says

Rare pair of neutron stars destined for explosion may reveal how heavy elements form in Universe, study says

Astronomers have spotted the first example of an extremely rare type of star system that is destined to one day blow up in an “ultra-powerful” gold-producing explosion.

Such types of stars fated to become “kilonova” explosions are so rare that only about 10 such systems are known to exist in the entire Milky Way Galaxy, said scientists from the Embry-Riddle Aeronautical University in the US.

Studying these systems destined to blow up can unravel how such explosions form, and also throw light on the origin of the heaviest elements in the universe, such as gold, uranium and thorium, scientists pointed out.

Previous research had shown these explosions occured when two extremely small and dense cosmic entities, known as neutron stars, merged.

Researchers describe the newly 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, scientists could deduce the orbital characteristics and types of stars that made up this system.

They found this star system was strangely made 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 need to explode as an ultra-stripped supernova so the two neutron stars could eventually collide and merge,” study co-author Noel D Richardson, from the Embry-Riddle Aeronautical University, explained in a statement.

“For quite some time, astronomers speculated about the exact conditions that could eventually lead to a kilonova,” said André-Nicolas Chené, another study author.

“These new results demonstrate that, in at least some cases, two sibling neutron stars can merge when one of them was created without a classical supernova explosion,” Dr Chene said.

While the Milky Way is known to contain at least 100 billion stars, such kilonova are so rare that the binary system that leads to them is “essentially a one-in-ten-billion system”.

“Prior to our study, the estimate was that only one or two such systems should exist in a spiral galaxy like the Milky Way,” Dr Chene explained.

However, scientists said the explosion is not imminent.

It could take at least a million years for the massive star to end its life and leave behind a second neutron star.

Afterwards, when the two neutron stars eventually merge, the resulting kilonova explosion will produce powerful gravitational waves and leave behind large amounts of heavy elements like gold and silver, explained scientists.