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相关论文: Lithium Abundances in a Sample of Planet Hosting D…

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A five-dimensional interpolation method and corresponding computer program are developed for using published calculations to determine the non-LTE correction {\Delta\}NLTE to the lithium abundance log{\epsilon}(Li) derived from the Li I…

太阳与恒星天体物理 · 物理学 2017-10-18 L. S. Lyubimkov , D. V. Petrov

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

High resolution (R=110000), very high S/N spectra, centered on the 6707.8A LiI line have been obtained with the ESO Coude Echelle Spectrometer for five, metal-poor (-0.8 < [Fe/H] < -0.6) disk stars in the turnoff region of the HR-diagram.…

天体物理学 · 物理学 2007-05-23 P. E. Nissen , D. L. Lambert , F. Primas , V. V. Smith

Lithium and zirconium abundances (the latter taken as representative for s-process enrichment) are determined for a large sample of massive Galactic O-rich AGB stars, for which high resolution optical spectroscopy has been obtained…

天体物理学 · 物理学 2009-11-11 D. A. Garcia-Hernandez , P. Garcia-Lario , B. Plez , A. Manchado , F. D'Antona , J. Lub , H. Habing

Lithium abundance in most of the warm metal-poor main sequence stars shows a constant plateau (A(Li)~2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites,…

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 present the [X/H] trends as function of the elemental condensation temperature Tc in 88 planet host stars and in a volume-limited comparison sample of 33 dwarfs without detected planetary companions. We gathered homogeneous abundance…

天体物理学 · 物理学 2009-11-11 A. Ecuvillon , G. Israelian , N. C. Santos , M. Mayor , G. Gilli

We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance…

太阳与恒星天体物理 · 物理学 2015-05-13 K. Lind , M. Asplund , P. S. Barklem

The lithium abundances in metal-poor halo stars are of importance for cosmology, galaxy evolution and stellar structure. In an attempt to study possible systematic errors in the derived Li abundances, the line formation of LiI lines has…

天体物理学 · 物理学 2011-05-23 M. Asplund , M. Carlsson , A. Botnen

Planetary engulfment events can occur while host stars are on the main sequence. The addition of rocky planetary material during engulfment will lead to refractory abundance enhancements in the host star photosphere, but the level of…

太阳与恒星天体物理 · 物理学 2022-09-21 Jason Sevilla , Aida Behmard , Jim Fuller

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

We report the discovery of a peculiar set of old super-metal-rich dwarf stars with orbits of low eccentricity that reach a maximum height from the Galactic plane between $\sim$ 0.5-1.5 kpc observed by the \emph{Gaia}-ESO Survey. These stars…

太阳与恒星天体物理 · 物理学 2025-01-29 M. L. L. Dantas , R. Smiljanic , R. Boesso , H. Rocha-Pinto , L. Magrini , G. Guiglion , D. Romano

The lithium present in the photospheres of solar-type stars is transported to the inner parts by convection, reaching regions even somewhat below the convection zone, by non-standard transport mechanisms. In stars with deeper convective…

太阳与恒星天体物理 · 物理学 2023-05-04 Giulia Martos , Jorge Meléndez , Anne Rathsam , Gabriela Carvalho Silva

Lithium abundances in a selected sample of halo stars have been revised by using the new accurate IRFM effective temperatures by Alonso, Arribas & Martinez-Roger (1996a). From 41 plateau stars (Teff > 5700 and [Fe/H] <= -1.5) we found no…

天体物理学 · 物理学 2015-06-24 Piercarlo Bonifacio , Paolo Molaro

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

We present VLT-UVES Li abundances for 28 halo dwarf stars between [Fe/H]=-2.5 and -3.5, 10 of which have [Fe/H]<-3. Four different T_eff scales have been used. Direct Infrared Flux Method (IRFM) has been used on the basis of 2MASS infrared…

Dwarf stars with debris discs and planets appear to be excellent laboratories to study the core accretion theory of planets formation. These systems are however, insufficiently studied. In this paper we present the main metallicity and…

太阳与恒星天体物理 · 物理学 2019-06-12 C. Chavero , R. de la Reza , L. Ghezzi , F. Llorente de Andrés , C. B. Pereira , C. Giuppone , G. Pinzón , .

A highly homogeneous study of 23 halo field dwarf stars has achieved a Li abundance accuracy of 0.033 dex per star. The work shows that the intrinsic spread of the Li abundances of these stars at a given metallicity is <0.02 dex, and…

天体物理学 · 物理学 2007-05-23 Sean G. Ryan

We have determined Li abundances for eleven metal-poor turn-off stars, among which eight have [Fe/H]<-3, based on LTE analyses of high-resolution spectra obtained with the HDS on the Subaru telescope. The Li abundances for four of these…

Lithium abundances are presented and discussed for 70 members of the 50 Myr old open cluster alpha Per. More than half of the abundances are from new high-resolution spectra. The Li abundance in the F-type stars is equal to its presumed…

太阳与恒星天体物理 · 物理学 2015-05-19 Suchitra C. Balachandran , Sushma V. Mallik , David L. Lambert