It was traditionally supposed that a large fraction of Li-rich low-mass evolved stars were at the red giant branch (RGB) stage, whereas recent studies report that the red clump (RC) stars, in which helium are burning at the cores, are more frequent than RGB stars. By monitoring the ‘heartbeats’ using asteroseismic approach to a large sample of such stars, we provide clear evidence that the majority of Li-rich stars are at the RC stage, and their Li abundances are higher than those of the RGB stars on average.
The combination of spectroscopy and asteroseismology is the key factor for obtaining those results (figure 1). Seven telescopes worldwide, including the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST), Subaru, and Kepler, have been used for data collecting. The observations lasted for years from 2015. Here I would like to share the story about the observations in our study.