Related papers: Li-rich and super Li-rich giants produced by eleme…
High lithium-7 ($\mathrm{^7Li}$) abundances in giants are indicative of non-standard physical processes affecting the star. Mechanisms that could produce this signature include contamination from an external source, such as planets, or…
Stars destroy lithium (Li) in their normal evolution. The convective envelopes of evolved red giants reach temperatures of millions of K, hot enough for the 7Li(p,alpha)4He reaction to burn Li efficiently. Only about 1% of first-ascent red…
The recent discovery of low-mass red giants with enhanced atmospherical Li abundance in galactic low-metallicity stellar clusters adds to the mysterious phenomenon of the Li-rich giants. We propose a combined scenario for the Li-enrichment:…
Li-rich giants serve as valuable tracers of stellar evolution and surface enrichment processes, for which a statistically large and homogeneous sample is crucial. Using the massive low-resolution ($R \sim 1800$) spectroscopic dataset from…
The discrepancy between cosmological Li abundance inferred from Population II dwarf stars and that derived from WMAP/BBNS is still far from being solved.We investigated, as an alternative route, the use of Li abundances in Population II…
A recent study of Li abundances in field red giant stars suggested that the phenomenon of enriched surface Li may be a short-lived phase of red clump evolution for stars with masses near 2 M_sun. Although the exact mechanism for generating…
Lithium is one of the few elements produced during the Big Bang Nucleosynthesis in the early universe. Moreover, its fragility makes it useful as a proxy for stellar environmental conditions. As such, the lithium abundance in old systems is…
Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron-Fowler conveyor, but the existence of Li-rich, low-mass red giant…
Lithium is a fragile but crucial chemical element in the universe, exhibits interesting and complex behaviors. Thanks to the massive spectroscopic data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)…
The orders of magnitude variation in lithium abundances of evolved stars have long been a puzzle. Diluted signals, ambiguous evolutionary states and unknown masses have made it challenging to both map the expected lithium signals and…
The discovery of Li-rich giant has cast a new challenge for the standard stellar evolution models, and to resolve this issue, the number of this type object has been rapidly increased because of the development of worldwide surveys these…
Surface lithium is depleted when a star goes through the first dredge-up phase, yet $1\%$ of red giants are found to be Li-rich. The formation mechanism for these remains uncertain. We combine observational constraints from GALAH Li-rich…
Theoretical models of stellar evolution predict that most of the lithium inside a star is destroyed as the star becomes a red giant. However, observations reveal that about 1% of red giants are peculiarly rich in lithium, often exceeding…
We report novel observational evidence on the evolutionary status of lithium-rich giant stars by combining asteroseismic and lithium abundance data. Comparing observations and models of the asteroseismic gravity-mode period spacing…
About 1% of giant stars have been shown to have large surface Li abundances, which is unexpected according to standard stellar evolution models. Several scenarios for lithium production have been proposed, but it is still unclear why these…
A model scenario has recently been introduced to explain the presence of very strong Li lines in the spectra of some low mass K giant stars (de la Reza et al. 1996). In this scenario all ordinary, Li poor, K giants become Li rich during a…
Since 7Li is easily destroyed in low temperatures, the surface lithium abundance decreases as stars evolve. This is supported by the lithium depletion observed in the atmosphere of most red giants. However, recent studies show that almost…
The surface lithium abundance A(Li) of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H]~-2.8 dex, while at lower metallicities the average value drops by 0.3 dex with a significant star-by-star scatter (called lithium…
The vast majority of stars with mass similar to the Sun are expected to only destroy lithium over the course of their lives, via low-temperature nuclear burning. This has now been supported by observations of hundreds of thousands of red…
Planetary engulfment events have long been proposed as a lithium (Li) enrichment mechanism contributing to the population of Li-rich giants (A(Li) >= 1.5 dex). Using MESA stellar models and A(Li) abundance measurements obtained by the GALAH…