Lithium is becoming common in our everyday lives. It is the key ingredient in the batteries of our mobile phones and electric vehicles, but have you ever wondered where it comes from? A new study that was published in Nature Astronomy and was led by Prof. ZHAO Gang and Dr. Yerra Bharat Kumar from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) provides a fresh understanding of both how it is made, and how it is destroyed.
Researchers studied the lithium content of hundreds of thousands of Sun-like stars to understand how this element changes over time in stars. Dr. Yerra Bharat Kumar, the first author of the study, said:
“Lithium is quite a special element. Our study challenges the idea that stars like the Sun only destroy lithium through their lives. Our observations show that they actually create it later in their lives, after they have swelled to become red giants. This means that the Sun itself will also manufacture lithium in the future.”
Lithium was produced in the Big Bang
Lithium is one of the three elements produced in the Big Bang. It gets destroyed very easily inside stars where it is too hot for it to survive, so its content generally decreases as stars age. Since it is such a sensitive element, it is very useful for understanding stars. It acts as a tracer for what is happening inside stars.
This Hubble Space Telescope image shows stars at various stages of their lives, from young blue-hot stars to cooler red giants. Our study focused on the lithium content of red giant stars. (Image: T. Brown (STScI) via NASA, ESA)
To better understand this sensitive element, researchers used data from a huge Chinese stellar spectroscopic survey based on The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The survey is currently building a database of the spectra of 10 million stars. This study also utilized data from the Australian star survey known as GALAH. Dr. Yerra Bharat Kumar said:
“By looking at starlight, we can determine what the stars are made of. Models show that our current theories about how stars evolve do not predict this lithium production at all. Thus, the study has created a tension between observations and theory.”
Prof. ZHAO Gang, the co-corresponding author of this study, added:
“Our findings will help us to better understand and model Sun-like stars. Since the newly created lithium will end up being blown off the star in stellar winds, it will also help us understand how these stars contribute to the lithium content of our Galaxy, and to planets like Earth.”
Provided by: Chinese Academy of Sciences [Note: Materials may be edited for content and length.]
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