Recently Indian researchers have discovered hundreds of Li-rich giant stars produced during BBN indicating that Li is being produced in the stars and accounts for its abundance in the interstellar medium.
About Big Bang Nucleosynthesis (BBN)
- BBN is the production of nuclei other than those of the lightest isotope of hydrogen during the early phases of the Universe.
- Primordial nucleosynthesis is believed by most cosmologists to have taken place in the interval from roughly 10 seconds to 20 minutes after the Big Bang.
- It is calculated to be responsible for the formation of most of the universe’s helium in various isotopic forms.
- Essentially all of the elements that are heavier than lithium were created much later, by stellar nucleosynthesis in evolving and exploding stars.
Lithium in space
- Lithium (Li), is one of the three primordial elements, apart from Hydrogen and Helium (He), produced in the Big Bang Nucleosynthesis (BBN).
- However, the present measurement of Li in the interstellar medium and very young stars is about 4 times more than the primordial value.
- Thus, identifying sources of Li enrichment in our Galaxy has been a great interest to researchers to validate BBN as well as a stellar mixing process.
- In general, stars are considered as Li sinks. This means that the original Li, with which stars are born, only gets depleted over stars’ life-time as Li burns at relatively very low temperatures.