While there is consensus that our Sun formed about 4.6 billion years ago from a molecular cloud of gas and dust, less has been known about how long the formation of the star actually took.
But now we have an estimate, thanks to stellar evolution tools pioneered by Monash University astrophysicists led by Associate Professor Amanda Karakas.
“From these models, we can determine which elements are produced by stars and how those elements are expelled into the galaxy,” Karakas explains. “This is crucial for understanding what made up the gas and dust our Sun formed from.”
An estimate of the Sun’s genesis was made possible by an international collaboration which first involved a Canadian particle accelerator programme finding the half-life of bare thallium-205, then a Hungarian observatory estimating the effects of this half-life on the production of radioactive lead in stars, based on Monash models of ageing red giants.
The results, published in Nature during November 2024, estimate that the Sun took between 10 and 20 million years to form. The study also confirms this exotic form of lead decay as a useful chronometer for the early Solar System.
c.NASA/GSFC/SDO
