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相关论文: Lithium Enrichment Signatures of Planetary Engulfm…

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Recent surveys have revealed a lack of close-in planets around evolved stars more massive than 1.2 Msun. Such planets are common around solar-mass stars. We have calculated the orbital evolution of planets around stars with a range of…

地球与行星天体物理 · 物理学 2014-11-20 Eva Villaver , Mario Livio

We investigate stellar elemental abundance patterns at z = 0 in 8 low-mass (M_* = 10^6 - 10^9 M_sun) galaxies in the Feedback in Realistic Environments (FIRE-2) cosmological simulations. Using magnesium (Mg) as a representative…

With its origin coming from several sources (Big Bang, stars, cosmic rays) and given its strong depletion during its stellar lifetime, the lithium element is of great interest as its chemical evolution in the Milky Way is not well…

The lithium abundances in a few percent of giants exceed the value predicted by the standard stellar evolution models, and the mechanisms of Li enhancement are still under debate. The Large Sky Area Multi-Object Fiber Spectroscopic…

太阳与恒星天体物理 · 物理学 2018-07-18 Y. T. Zhou , J. R. Shi , H. L. Yan , Q. Gao , J. B. Zhang , G. Zhao , K. Pan , Y. B. Kumar

Transport processes occurring in the radiative interior of solar-type stars are evidenced by the surface variation of light elements, in particular Li, and the evolution of their rotation rates. For the Sun, inversions of helioseismic data…

太阳与恒星天体物理 · 物理学 2021-02-10 T. Dumont , A. Palacios , C. Charbonnel , O. Richard , L. Amard , K. Augustson , S. Mathis

Lithium is an important element for the understanding of ultracool dwarfs because it is lost to fusion at masses above $\sim 68\, M_{\rm J}$. Hence, the presence or absence of atomic Li has served as an indicator of the nearby H-burning…

太阳与恒星天体物理 · 物理学 2021-09-29 Ehsan Gharib-Nezhad , Mark S. Marley , Natasha E. Batalha , Channon Visscher , Richard S. Freedman , Roxana E. Lupu

We previously explored the circumstellar effects on the Rb and Zr abundances in massive Galactic O-rich AGB stars. Here we are interested in the role of the extended atmosphere in the case of Li and Ca. Li is an important indicator of HBB…

太阳与恒星天体物理 · 物理学 2019-03-27 V. Pérez-Mesa , O. Zamora , D. A. García-Hernández , Y. Osorio , T. Masseron , B. Plez , A. Manchado , A. I. Karakas , M. Lugaro

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…

太阳与恒星天体物理 · 物理学 2012-05-31 Evan Kirby , Xiaoting Fu , Puragra Guhathakurta , Licai Deng

Aims. To explore the possible chemical signature of planet formation in the binary system HAT-P-4, by studying abundance vs condensation temperature Tc trends. The star HAT-P-4 hosts a planet detected by transits while its stellar companion…

太阳与恒星天体物理 · 物理学 2017-08-02 C. Saffe , E. Jofré , E. Martioli , M. Flores , R. Petrucci , M. Jaque Arancibia

[ABRIDGED] We determine Li abundances for a well-studied sample of 714 F and G dwarf, turn-off, and subgiant stars in the solar neighbourhood. The analysis is based on line synthesis of the Li line at 6707 {\AA} in high-resolution and high…

星系天体物理 · 物理学 2018-08-01 Thomas Bensby , Karin Lind

We present the first detailed abundance analysis of the metal-poor giant HKII 17435-00532. This star was observed as part of the University of Texas long-term project "Chemical Abundances of Stars in the Halo" (CASH). A spectrum was…

We present a search for post-main-sequence field stars in the Galaxy with atypically large lithium abundances. Using moderate-resolution spectra taken as part of the Sloan Digital Sky Survey, along with high-resolution followup spectroscopy…

太阳与恒星天体物理 · 物理学 2015-06-12 Sarah L. Martell , Matthew D. Shetrone

Thanks to the high multiplex and efficiency of Giraffe at the VLT we have been able for the first time to observe the Li I doublet in the Main Sequence (MS) stars of a Globular Cluster. At the same time we observed Li in a sample of…

The cosmological {7Li problem consists in explaining why the primordial Li abundance, as predicted by the standard Big Bang nucleosynthesis theory with constraints from WMAP and Planck, is a factor of 3 larger than the Li abundance measured…

星系天体物理 · 物理学 2021-05-12 Francesca Matteucci , Marta Molero , David S. Aguado , Donatella Romano

Context. Galactic red novae are thought to be produced in stellar mergers between non-compact stars, such as main-sequence stars and cool giants. They are hoped to help in explaining physical processes involved in common envelope evolution…

太阳与恒星天体物理 · 物理学 2023-04-26 Tomek Kamiński , Mirek Schmidt , Marcin Hajduk , Aleksandra Kiljan , Inna Izviekova , Adam Frankowski

The observations of light elements in the Sun and Solar type stars give special clues for understanding the hydrodynamical processes at work in stellar interiors. In the Sun 7Li is depleted by 140 while 3He has not increased by more than…

天体物理学 · 物理学 2007-05-23 Sylvie Vauclair

We have determined precise stellar parameters and lithium abundances in a sample of 117 stars with basic properties very similar to the Sun. This sample selection reduces biasing effects and systematic errors in the analysis. We estimate…

太阳与恒星天体物理 · 物理学 2015-05-19 Patrick Baumann , Iván Ramírez , Jorge Meléndez , Martin Asplund , Karin Lind

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…

太阳与恒星天体物理 · 物理学 2021-03-17 Kanji Mori , Motohiko Kusakabe , A. Baha Balantekin , Toshitaka Kajino , Michael A. Famiano

A Li-rich red giant star (2M19411367+4003382) recently discovered in the direction of NGC 6819 belongs to the rare subset of Li-rich stars that have not yet evolved to the luminosity bump, an evolutionary stage where models predict Li can…

Extreme emission-line galaxies (EELGs) probe chemical enrichment in low-mass, bursty systems where star formation, feedback, and gas accretion are poorly constrained. Using DESI DR1, we select 23 nearby EELGs with detections of 19 ionic…