‘One in 10 billion’ binary star system discovered

Los astrónomos han descubierto un sistema estelar ‘fenomenalmente raro’ que algún día podría desencadenar una explosión enormemente poderosa que baña el espacio con oro.

El sistema ‘uno en 10 mil millones’ es tan escaso que se cree que solo existen 10 de este tipo en toda nuestra galaxia.

Tiene todas las condiciones adecuadas para eventualmente desencadenar una kilonova causada por la fusión de dos estrellas de neutrones, dicen expertos en los EE. UU., Creando una explosión 1.000 veces más brillante que una nova clásica.

La inusual agrupación de estrellas, conocida como CPD-29 2176, se encuentra a unos 11.400 años luz de la Tierra y fue identificada por primera vez por el Observatorio Neil Gehrels Swift de la NASA, que se lanzó al espacio en 2004.

Las observaciones de seguimiento con el Telescopio SMARTS de 1,5 metros en el Observatorio Interamericano Cerro Tololo en Chile permitieron a los astrónomos confirmar que el sistema algún día formará una kilonova.

Unusual: Astronomers have discovered a ‘phenomenal rare’ star system (shown in an artist’s impression) that could one day unleash an enormously powerful explosion that bathes space in gold.

This is because they can see that it contains a neutron star created by what is known as an ‘ultranaked supernova’, as well as a closely orbiting massive star that is in the process of becoming an ultranaked supernova.

An ultra-stripped supernova is different from a regular one in that it produces little or no ejection, or “kick,” which experts believe is because the exploding star has already been stripped of its outer atmosphere by a companion star.

WHAT IS A KILONOVA?
Kilonovae are huge explosions caused by neutron stars colliding with each other, sending an intense stream of high-energy particles through space.

They produce a bright flash of radioactive light that produces large amounts of important elements such as silver, gold, platinum, and uranium.

The merger between the two neutron stars, some of the densest objects in the universe, creates an explosion 1,000 times brighter than a classical nova.

The exploding star becomes a neutron star, but because its supernova lacks explosive force, it means the binary companion next to it isn’t lost.

A traditional supernova would eject a nearby companion star out of the system.

Instead of being ejected, the companion star often eventually becomes another neutron star, which is what provides the perfect ingredients for a kilonova to occur.

These are huge explosions caused by neutron stars colliding with each other, sending an intense stream of high-energy particles through space.

They produce a bright flash of radioactive light that produces large amounts of important elements such as silver, gold, platinum, and uranium.

CPD-29 2176 is unusual in that astronomers had always thought that for a kilonova to form at least one of the neutron stars, some of the densest objects in the universe, it had to be created from a traditional supernova explosion.

The new system suggests that this is not the case.

‘The current neutron star would have to form without ejecting its companion from the system. An ultra-stripped supernova is the best explanation for why these companion stars are in such a tight orbit,” said lead author Noel Richardson of Embry-Riddle Aeronautical University.

“To one day create a kilonova, the other star would also have to explode as an ultra-naked supernova so that the two neutron stars could collide and merge.”

Cycle: The system contains a neutron star created by an ultranaked supernova, as well as a closely orbiting massive star that is in the process of becoming an ultranaked supernova. This graph shows how the system started out as two massive stars (#1), before one became a neutron star and the other will now eventually do so and trigger a kilonova.

The researchers hope that their discovery will help unravel the mystery of how kilonovae form, which in turn would shed light on the origin of the heaviest elements in the universe.

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

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