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Earth`s gold may have originated from colliding dead stars

Last Updated: Thursday, July 18, 2013 - 09:46

Washington: Unlike elements like carbon or iron, gold cannot be created within a star instead it can only be formed by a cataclysmic event.

Observations of a short gamma-ray burst (GRB) has provided evidence that it resulted from the collision of two neutron stars - the dead cores of stars that previously exploded as supernovae.

Moreover, a unique glow, which persisted for days at the GRB location, potentially signifies the creation of substantial amounts of heavy elements - including gold.

Lead author Edo Berger of the Harvard-Smithsonian Center for Astrophysics (CfA), said that his team estimates that the amount of gold produced and ejected during the merger of the two neutron stars could be as much as 10 Moon masses.

A gamma-ray burst is a flash of high-energy light (gamma rays) from an extremely energetic explosion. Berger and his colleagues studied GRB 130603B which, at a distance of 3.9 billion light-years from Earth, is one of the nearest bursts seen to date.

Gamma-ray bursts come in two varieties-long and short-depending on how long the flash of gamma rays lasts. GRB 130603B, detected by NASA`s Swift satellite on June 3rd, lasted for less than two-tenths of a second.

Although the gamma rays disappeared quickly, GRB 130603B also displayed a slowly fading glow dominated by infrared light. Its brightness and behaviour didn`t match a typical "afterglow," which is created when a high-speed jet of particles slams into the surrounding environment.

Instead, the glow behaved like it came from exotic radioactive elements. The neutron-rich material ejected by colliding neutron stars can generate such elements, which then undergo radioactive decay, emitting a glow that`s dominated by infrared light - exactly what the team observed.

The team calculates that about one-hundredth of a solar mass of material was ejected by the gamma-ray burst, some of which was gold.

By combining the estimated gold produced by a single short GRB with the number of such explosions that have occurred over the age of the universe, all the gold in the cosmos might have come from gamma-ray bursts.

The results have been submitted for publication in The Astrophysical Journal Letters.


First Published: Thursday, July 18, 2013 - 09:46

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