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相关论文: Li-rich Giants Identified from LAMOST DR8 Low-Reso…

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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…

Standard stellar evolution model predicts a severe depletion of lithium (Li) abundance during the first dredge-up process (FDU). Yet a small fraction of giant stars are still found to preserve a considerable amount of Li in their…

Standard stellar evolution model predicts a severe depletion of lithium (Li) abundance during the first dredge up process (FDU). Yet a small fraction of giant stars are still found to preserve a considerable amount of Li in their…

太阳与恒星天体物理 · 物理学 2020-01-08 Qi Gao , Jian-Rong Shi , Hong-Liang Yan , Tai-Sheng Yan , Mao-Sheng Xiang , Yu-Tao Zhou , Chun-Qian Li , Gang Zhao

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…

太阳与恒星天体物理 · 物理学 2019-06-05 Yutao Zhou , Hongliang Yan , Jianrong Shi , S. Blanco-Cuaresma , Qi Gao , K. Pan , Xiaodong Xu , Junbo Zhang , Gang Zhao

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)…

In this work, we studied the distribution of lithium abundances in giants as a function of stellar mass. We used a sample of 1240 giants common among Kepler photometric and LAMOST medium resolution (R $\approx$ 7500) spectroscopic survey…

太阳与恒星天体物理 · 物理学 2023-02-13 Anohita Mallick , Raghubar Singh , Bacham E. Reddy

Context. About 0.2-2% of giant stars are Li-rich, whose lithium abundance (A(Li)) is higher than 1.5 dex. Among them, near 6% are super Li-rich with A(Li) exceeding 3.2 dex. Meanwhile, the formation mechanism of these Li-rich and super…

太阳与恒星天体物理 · 物理学 2022-12-14 Jun Gao , Chunhua Zhu , Jinlong Yu , Helei Liu , Xizhen Lu , Jianrong Shi , Guoliang Lü

Lithium-rich giant stars are rare and their existence challenges our understanding of stellar structure and evolution. We profit from the high-quality sample gathered with HARPS and UVES, in order to search for Li-rich giants and to…

太阳与恒星天体物理 · 物理学 2023-06-21 M. Tsantaki , E. Delgado-Mena , D. Bossini , S. G. Sousa , E. Pancino , J. H. C. Martins

We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including the first Li-rich giant with evolutionary stage confirmed by CoRoT data. Atmospheric parameters and abundances were derived in model atmosphere analyses…

Using the sample of 348 stars from the PennState-Torun Centre for Astronomy Planet Search, for which uniformly determined atmospheric parameters are available, with chemical abundances and rotational velocities presented here, we…

太阳与恒星天体物理 · 物理学 2015-06-22 M. Adamow , A. Niedzielski , E. Villaver , A. Wolszczan , G. Nowak

Context: Lithium is a fragile element, which is easily destroyed in the stellar interior. The existence of lithium-rich giants still represents a challenge for stellar evolution models. Aims: We have collected a large database of…

太阳与恒星天体物理 · 物理学 2015-05-27 L. Monaco , S. Villanova , C. Moni Bidin , G. Carraro , D. Geisler , P. Bonifacio , O. A. Gonzalez , M. Zoccali , L. Jilkova

In this study, we explore the evolution of lithium in giant stars based on data assembled from the literature on asteroseismology and Li abundances for giants. Our final sample of 187 giants consists of 44 red giant branch (RGB), 140 core…

太阳与恒星天体物理 · 物理学 2021-05-07 Deepak , David L. Lambert

With an aim to shed light on the origin of Li anomaly observed in a small fraction of red giants, we carried out a spectroscopic study on the observational characteristics of selected 20 bright Li-rich giants, in comparison with a large…

太阳与恒星天体物理 · 物理学 2017-09-20 Yoichi Takeda , Akito Tajitsu

A small fraction of red giants are known to be lithium (Li) rich, in contradiction with expectations from stellar evolutionary theory. A possible explanation for these atypical giants is the engulfment of a Li-rich planet or brown dwarf by…

太阳与恒星天体物理 · 物理学 2016-10-05 Claudia Aguilera-Gómez , Julio Chanamé , Marc Pinsonneault , Joleen Carlberg

The puzzle of Li-rich giant is still unsolved, contradicting the prediction of the standard stellar models. Although the exact evolutionary stages play a key role in the knowledge of Li-rich giants, a limited number of Li-rich giants have…

太阳与恒星天体物理 · 物理学 2022-06-15 Yutao Zhou , Chun Wang , Hongliang Yan , Yang Huang , Bo Zhang , Yuan-Sen Ting , Huawei Zhang , Jianrong Shi

About one percent of giants\upcite{Brown1989} are detected to have anomalously high lithium (Li) abundances in their atmospheres, conflicting directly with the prediction of the standard stellar evolution models\upcite{Iben1967}, and making…

Compositions of lithium-enriched and normal giants among the GALAH survey are compared. Except for Li, the only detectable abundance difference between lithium-enriched and normal giants among the investigated elements from carbon to…

太阳与恒星天体物理 · 物理学 2020-03-19 Deepak , David L. Lambert , Bacham Eswar Reddy

Stellar models predict that lithium (Li) inside a star is destroyed during the first dredge-up phase, yet 1.2% of red giant stars are Li-rich. We aim to uncover possible origins of this population, by analysing 1155 Li-rich giants (A(Li)…

In this article, we speculate on the possible mechanisms for Li enhancement origin in RGB stars based on a large data set of around 340,299 stars collected from the GALAH survey combined with the Gaia astrometry. Data has 51,982 low mass…

太阳与恒星天体物理 · 物理学 2019-01-29 Deepak , Bacham Eswar Reddy

We report the discovery of eight lithium-rich field giants found in a high resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H]<-0.5) selected from the RAVE survey. The majority of the Li-rich giants in our sample are very…

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