Stellar Gold and Silver

Nearly all elements, often excepting those lightest elements such as hydrogen, are produced in the stars. But not all elements are produced in all stars. Depending on the type of star, different elements may be produced during their life and death. Gold and silver, you, and everyone else are star stuff.

The optical double star Alpha Capricorni
The optical double star Alpha Capricorni

During their life, nuclear fusion occurs taking two atoms and fusing their nuclei to create a heavier element. The production of elements also occurs during the death of a star, which spreads the elements far. Our own star (the Sun or Sol) mostly produces helium from hydrogen, alongside slightly heavier elements (e.g. oxygen). But our sun does not create gold or silver, and these elements certainly don’t originate on the Earth, so where do they come from?

Some of the 2014 Russian Olympic medals were made using both precious metals and parts of a meteorite (that fell in 2013)
Some of the 2014 Russian Olympic medals were made using both precious metals and parts of a meteorite (that fell in 2013)

Determined in 2012 by astrophysicist Dr. Camilla Hansen, silver and gold are produced in entirely different ways. While gold can be made during the life of a star through typical fusion processes, silver is created during fusion unique to supernovae. After collecting the evidence, she had this to say:

This is the first incontrovertible evidence for a special fusion process taking place during the explosion of a star. Up to now this had been mere speculation. After this discovery, we must now use simulations of these processes in supernova explosions to investigate more precisely when the conditions for the formation of silver are present. That way we can find out how heavy the stars were that could produce silver during their dramatic demise.

The Crab Nebula is 95% helium
The Crab Nebula is 95% helium

Any two stars, with the same mass, that die will produce the exact same quantities of elements. The process for creating silver is so completely different, however, that the amounts of silver produced from star to star can vary. On top of this, gold and silver cannot possibly be produced from the same star. If both are sent out from a single supernova, that star must have been formed from the remains of another (silver in one, gold in the other).

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