Unlocking how the Sun was born

Using radioactive materials, researchers have investigated the solar system's prehistoric phase and the events that may have led to the Sun's birth.

The team used radioactivity to date the last time that heavy elements such as gold, silver, platinum, lead and rare-earth elements were added to the solar system matter by the stars that produced them.

"We can now tell with confidence the final one percent of gold, silver and platinum were added to the solar system matter roughly 100 million years before the birth of the sun," said researchers Maria Lugaro and Alexander Heger from Monash University's centre for astrophysics in Melbourne, Australia.

The final one percent of lead and rare-earth elements such as those that make your smartphone, were added much later - at most, 30 million years before the birth of the sun, they added.

The detailed timing opened up new opportunities to understand the series of events that led to the formation of the sun.

Some time after the last addition of heavy elements, the solar system matter went into an "incubation" period, during which time the stellar nursery formed - where the Sun was born together with a number of other stars.

"We now know this incubation period could not have lasted more than 30 million years. This offers us the chance to determine the lifespan of the nursery where the Sun was born, how massive it was and how many stars were born there together," Lugaro explained.

Understanding the time-scale and processes leading to the formation of our solar system is key to relate its birth environment with that of other planetary systems in the galaxy, he noted.

The findings were published in the journal Science.