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相关论文: Probing infrared excess connection with Li enhance…

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To understand the underlying mechanisms for high lithium abundances among core He-burning or red clump (RC) giants, we analyzed a sample of 5227 RC giants of mass M $\leq$ 2~M$_{\odot}$ using spectra and asteroseismic data. We found 120 RC…

太阳与恒星天体物理 · 物理学 2025-08-06 Raghubar Singh , Bacham E. Reddy , Anohita Mallick , Gang Zhao

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

We searched for a correlation between the two anomalous properties of K giants: Li enhancement and IR excess from an unbiased survey of a large sample of RGB stars. A sample of 2000 low-mass K giants with accurate astrometry from the…

太阳与恒星天体物理 · 物理学 2015-04-29 Y. Bharat Kumar , B. E. Reddy , C. Muthumariappan , G. Zhao

Lithium abundances for red giants in the GALAH DR3 survey are studied. The rare examples of Li-enriched stars with abundances A(Li) $\geq 1.5$ are confirmed to be He-core burning stars belonging to or evolved from the red clump with similar…

太阳与恒星天体物理 · 物理学 2021-08-25 Deepak , David L. Lambert

Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using IRAS data, and past studies have suggested a link between RGs with overabundant Li and IR excesses, implying the ejection of circumstellar shells or…

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

In this paper we report two new super Li-rich K giants: KIC 2305930 and KIC 12645107 with Li abundances exceeding that of ISM (A(Li) $\geq$ 3.2 dex). Importantly, both the giants have been classified as core He-burning red clump stars based…

太阳与恒星天体物理 · 物理学 2018-05-23 Yerra Bharat Kumar , Raghubar Singh , B. Eswar Reddy , 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

We present a study of correlations between high Li abundances and strong chromospheric He I 10830 \AA\ absorption line strengths in Kepler field giant stars. Our sample includes 84 giants with detectable solar-like oscillations in their…

太阳与恒星天体物理 · 物理学 2025-01-16 Anohita Mallick , Christopher Sneden , Bacham E. Reddy , Melike Afşar

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

Given the implications for the origin of Li enhancement in red giants we have reviewed Li-rich classification of KIC~9821622, the only bonafide RGB giant with He inert-core till date, reported as a Li-rich giant by reanalyzing the…

太阳与恒星天体物理 · 物理学 2020-01-08 Raghubar Singh , Bharat Kumar Yerra , Bacham E. Reddy , Wako Aoki

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…

太阳与恒星天体物理 · 物理学 2014-08-13 Joleen K. Carlberg , Katia Cunha , Verne V. Smith

The presence of a large amount of Li in giants is still a mystery. Most of the super Li-rich giants reported in recent studies are in the solar metallicity regime. Here, we study the five metal-poor super Li-rich giants (SLRs) from GALAH…

太阳与恒星天体物理 · 物理学 2024-03-26 Antony Susmitha , Anohita Mallick , Bacham E. Reddy

In this letter, we report the discovery of 24 new super Li-rich (A(Li) $\ge$ 3.2) giants of He-core burning phase at red clump region. Results are based on systematic search of a large sample of about 12,500 giants common to the LAMOST…

太阳与恒星天体物理 · 物理学 2019-06-19 Raghubar Singh , Bacham E. Reddy , Yerra Bharat Kumar , H. M. Antia

It has recently been suggested that all giant stars with mass below 2 $M_{\odot}$ suffer an episode of surface lithium enrichment between the tip of the red giant branch (RGB) and the red clump (RC). We test if the above result can be…

In this Letter, we report on a low-resolution spectroscopic survey for Li-rich K giants among 2000 low mass (M <= 3 Msun) giants spanning the luminosity range from below to above the luminosity of the clump. Fifteen new Li-rich giants…

太阳与恒星天体物理 · 物理学 2015-05-27 Yerra Bharat Kumar , Bacham E. Reddy , David L. Lambert

A few percent of red giants are enriched in Lithium with $A(\mathrm{Li}) > 1.5$. Their evolutionary status has remained uncertain because these Li-rich giants can be placed both on the red-giant branch (RGB) near the bump luminosity and in…

太阳与恒星天体物理 · 物理学 2024-10-21 Pavel A. Denissenkov , Simon Blouin , Falk Herwig , Jacob Stott , Paul R. Woodward

Although not predicted by standard stellar evolution, the surface abundance of light elements, such as lithium (Li), carbon, and nitrogen, changes during the red giant branch (RGB) as a result of extra-mixing. This is associated usually…

太阳与恒星天体物理 · 物理学 2023-02-08 Claudia Aguilera-Gómez , Matías I. Jones , Julio Chanamé

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…

太阳与恒星天体物理 · 物理学 2016-03-10 Evan N. Kirby , Puragra Guhathakurta , Andrew J. Zhang , Jerry Hong , Michelle Guo , Rachel Guo , Judith G. Cohen , Katia Cunha

The aim of this work is to search for Li-rich giants in a sample of clusters where planets have been searched, thus we can study the planet engulfment scenario to explain Li replenishment using a proper comparison sample of stars without…

太阳与恒星天体物理 · 物理学 2016-02-17 E. Delgado Mena , M. Tsantaki , S. G. Sousa , M. Kunitomo , V. Adibekyan , P. Zaworska , N. C. Santos , G. Israelian , C. Lovis
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