Gold could have formed from star collision
A team of researchers at the Aristotle University of Thessaloniki, Greece, have been studying the collision of two neutron stars in computer simulations.
Lead author Dr Andreas Bauswein, whose work is supported by the EU’s and Horizon 2020’s Marie Skłodowska-Curie Actions, concludes that these small celestial objects are formed when massive stars collapse.
Bauswein said: “The formation of heavy elements is a major topic in stellar astrophysics. We want to understand where and how elements like gold and uranium were produced.
“There has been a kind of paradigm change in the last, say, five years. All recent simulations of supernovae find conditions that are not favourable for very heavy element formation.”
Our own fairly small star, the Sun, can generate helium by fusing pairs of atoms of the lightest element, hydrogen, at temperatures of millions of degrees. Elements heavier than helium – carbon, oxygen, nitrogen and so on – must be generated in bigger stars.
Even the biggest stars, however, cannot produce elements such as gold and uranium. Until recently, physicists believed that these elements could be forged only when massive stars go supernova.
Dr Philippe André at the Astrophysics Laboratory of the French Alternative Energies and Atomic Energy Commission in Paris-Saclay, whose research is funded by the European Research Council, added: “This area of science is particularly interesting for me because it relates to the question of the origin of our own solar system. We cannot understand the universe without understanding the formation of stars.”
André’s research suggests that stars tend to form along dense filaments within interstellar clouds. These unstable filaments then begin to break up into ‘regular-sized chunks’ under pressure from gravitational waves, contributing to a star’s overall size.
The new research indicates that all heavy elements, including gold, are created in colliding neutron stars, and not in supernovae as previously believed.
