Lithium is almost entirely destroyed as stars evolve up the red giant branch — yet a small fraction of red giants show lithium abundances far exceeding theoretical predictions. The origin of this lithium enrichment remains one of the outstanding puzzles in stellar astrophysics. This project aims to investigate these enigmatic stars using asteroseismology, the study of stellar oscillations. Stellar oscillations act like seismic waves in stars, carrying information from their outer layers down to their cores. By analysing these oscillations, we can probe the internal structure of stars and search for signatures of the processes responsible for lithium enrichment.
What you will do
The student will work with high-precision photometric data from the Kepler space telescope, focusing on the oscillation spectra of helium-burning red giants. The project will involve:
- Extracting and analysing the characteristic oscillation frequencies of these stars, with particular attention to mixed modes i.e., the oscillations sensitive to both the core and envelope.
- Applying statistical techniques to measure and compare oscillation properties between “normal” helium-burning red giants and their lithium-enriched counterparts.
- Using both stellar models and data-driven machine methods to identify subtle differences in the oscillation power spectra that could indicate unusual internal processes.
Skills you will develop
Spectroscopic survey analysis, asteroseismology, stellar evolution theory, statistical methods.
Why this matters
Understanding lithium enrichment in red giants has direct implications for Galactic chemical evolution and the cosmic lithium problem — the long-standing discrepancy between the observed and predicted primordial lithium abundance.
If you want to know more, please get in touch via email.