Topics Covered: Awareness in space.
Lithium rich red giants
What to study?
For Prelims: What are red giants and what is Li?
For Mains: Significance of these findings.
Context: Researchers at the Indian Institute of Astrophysics (IIA), an autonomous institute under the Department of Science &Technology, Govt. of India, have discovered hundreds of Li-rich giant stars.
They have also associated such Li enhancement with central He-burning stars, also known as red clump giants, thereby opening up new vistas in the evolution of the red giant stars.
This discovery indicates that Li is being produced in the stars and accounts for its abundance in the interstellar medium.
Identifying sources of Li enrichment in our Galaxy has been a great interest to researchers to validate Big Bang Nucleosynthesis as well as a stellar mixing process.
Lithium (Li), is one of the three primordial elements, apart from Hydrogen and Helium (He), produced in the big bang nucleosynthesis (BBN).
Li in stars:
Stars are proposed as likely Li source in the Galaxy. 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 of about 2.5X106 K – a range which is easily encountered in stars.
What is the big bang nucleosynthesis (BBN)?
The Big Bang Nucleosynthesis theory predicts that roughly 25% the mass of the Universe consists of Helium. It also predicts about 0.01% deuterium, and even smaller quantities of lithium.
It 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.