New Delhi, Nov 30:  Scientists have found a clue to the mystery behind the high abundance of Lithium – a trace element on Earth and a key component of rechargeable batteries – in some evolved stars.

For more than four decades, astronomers have known that a class of stars has an anomalous amount of Lithium on their surface. The reason and processes behind the high abundance of Lithium in about one percent of red giants have remained a puzzle since the models of how stars evolve predict the Lithium must have been destroyed in the hot plasma of the star.

They created virtual stars of various masses and metallicity and compared the properties of these virtual stars with that of real stars from the GALAH survey. These comparisons confirmed that all the lithium-rich stars are burning helium in their core.

In a separate study, the researchers combined information about oscillations in stars’ interiors with their lithium abundances to find the origin of lithium-rich giant stars. For this study, they collected asteroseismic data (i.e., information about oscillations in stars’ interiors) for giant stars with measured lithium abundances. They found that all the lithium-rich giant stars are burning helium in their core.