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相关论文: The lithium-rotation connection in the newly disco…

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We investigate the history of $^6$Li and $^7$Li in population II dwarfs during the pre main sequence and main sequence. The evolution is followed using the CESAM code and taking into account the most recent physics. The effective…

天体物理学 · 物理学 2007-05-23 Laurent Piau

We investigate the distribution of the lithium abundances, A(Li), of metal-poor dwarf and subgiant stars within the limits 5500 K < Teff < 6700 K, -6.0 < [Fe/H] < -1.5, and logg > ~3.5 (a superset of parameters first adopted by Spite and…

太阳与恒星天体物理 · 物理学 2023-04-05 J. E. Norris , D. Yong , A. Frebel , S. G. Ryan

The method of gyrochronology relates the age of its star to its rotation period. However, recent evidence of deviations from gyrochronology relations was reported in the literature. Here, we study the influence of tidal interaction between…

太阳与恒星天体物理 · 物理学 2020-10-28 A. Oetjens , L. Carone , M. Bergemann , A. Serenelli

We present high-resolution spectroscopic observations of the \ion{Li}{1} resonance line in a sample of 62 stars that belong to 31 common-proper motion pairs with twin F or G-type components. Photospheric abundances of lithium were derived…

天体物理学 · 物理学 2009-11-07 Eduardo L. Martin , Gibor Basri , Yakiv Pavlenko , Yuri Lyubchik

Recent observational work by Israelian et al. has shown that sun-like planet host stars in the temperature range 5700K < Teff < 5850K have lithium abundances that are significantly lower than those observed for "single" field stars. In this…

太阳与恒星天体物理 · 物理学 2015-05-18 S. G. Sousa , J. Fernandes , G. Israelian , N. C. Santos

We aim at constraining the angular momentum evolution of low mass stars by measuring their rotation rates when they begin to evolve freely towards the ZAMS, i.e. after the disk accretion phase has stopped. We conducted a multi-site…

Li abundances are derived for a sample of bulgelike stars with isochronal ages of 10-11 Gyr. These stars have orbits with pericentric distances, Rp, as small as 2-3 kpc and Zmax < 1 kpc. The sample comprises G and K dwarf stars in the…

天体物理学 · 物理学 2009-11-07 Luciana Pompeia , Beatriz Barbuy , Michel Grenon , Bruno Castilho

Lithium is a fundamental element for studying the mixing mechanisms acting in the stellar interiors, for understanding the chemical evolution of the Galaxy and the Big Bang nucleosynthesis. The study of Li in stars of open clusters…

太阳与恒星天体物理 · 物理学 2015-06-15 P. Francois , L. Pasquini , K. Biazzo , P. Bonifacio , R. Palsa

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

We present the initial results of a study of the surface lithium abundance in a sample of low-mass members (M~0.4-1.0 Msun) of the Orion Nebula Cluster (ONC) that provide an independent clock to estimate stellar ages. We report discovery of…

天体物理学 · 物理学 2009-11-11 F. Palla , S. Randich , E. Flaccomio , R. Pallavicini

Reconstructing the Galactic evolution of lithium (Li) is the main tool used to constrain the source(s) of Li enrichment in the Galaxy. Recent results have suggested a decline in Li at supersolar metallicities, which may indicate reduced…

We present stellar rotation rates derived from Transiting Exoplanet Survey Satellite (TESS) light curves for stars in Upper Centaurus-Lupus (UCL; ~136 pc, ~16 Myr) and Lower Centaurus-Crux (LCC; ~115 pc, ~17 Myr). We find spot-modulated…

太阳与恒星天体物理 · 物理学 2022-08-17 L. M. Rebull , J. R. Stauffer , L. A. Hillenbrand , A. M. Cody , Ethan Kruse , Brian P. Powell

The "Li-Dip" is an unexpected, striking, and highly non-standard anomaly of severe lithium depletion observed in mid-F dwarf stars, which has puzzled astronomers for nearly 40 years. Mechanisms proposed to explain the Li-Dip include effects…

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

The lines of lithium at 6708 A, and 6103 A, are analyzed in high resolution spectra of some sharp-lined and slowly rotating roAp stars. Three spectral synthesis codes - STARSP, ZEEMAN2 and SYNTHM were used. New lines of the rare earth…

[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 results of a ground-based programme conducted on 1-4m class telescopes. Our sample consists of 1097 active and presumably young stars, all of them being optical counterparts of RASS X-ray sources in the northern…

太阳与恒星天体物理 · 物理学 2015-05-13 P. Guillout , A. Klutsch , A. Frasca , R. Freire Ferrero , E. Marilli , G. Mignemi , K. Biazzo , J. Bouvier , R. Monier , C. Motch , M. Sterzik

We have computed a grid of up-to-date stellar evolutionary models including atomic diffusion, in order to study the evolution with time of the surface Li abundance in low-mass metal-poor stars. We discuss in detail the dependence of the…

天体物理学 · 物理学 2009-11-06 Maurizio Salaris , Achim Weiss

We present high resolution observations (FWHM=15 km/sec) of the Li region in 5 stars belonging to the old (14 Gyrs), metal rich ([Fe/H]=-0.7) globular cluster 47Tuc. At the ESO NTT telescope we obtained EMMI spectra for three V about 17.4…

天体物理学 · 物理学 2011-05-23 Luca Pasquini , Paolo Molaro

Young stars in the solar neighborhood serve as nearby probes of stellar evolution and represent promising targets to directly image self-luminous giant planets. We have carried out an all-sky search for late-type ($\approx$K7$-$M5) stars…