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相关论文: 3D Hydrodynamical Simulations of a Brown Dwarf Acc…

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In this work, we study whether the engulfment of a brown dwarf (BD) by a solar-like main-sequence (MS) star can significantly alter the structure of the star and the Li content on its surface. We perform 3D Smoothed Particle Hydrodynamics…

太阳与恒星天体物理 · 物理学 2023-02-22 Rubén M. Cabezón , Carlos Abia , Inma Domínguez , Domingo García-Senz

The study of lithium (Li) surface abundance in the Sun and young stellar globular clusters which are seemingly anomalous in present-day scenarios, as well as the influence of rotation and magnetic braking (MB) on its depletion during…

太阳与恒星天体物理 · 物理学 2020-07-01 R. Caballero Navarro , A. García Hernández , A. Ayala , J. C. Suárez

The engulfment of substellar bodies (SBs, such as brown dwarfs and planets) by giant stars is a possible explanation for rapidly rotating giants, lithium-rich giants, and the presence of SBs in close orbits around subdwarfs and white…

We investigate the impact of 3D hydrodynamical model atmospheres of red giant stars at different metallicities on the formation of spectral lines of a number of ions and molecules. We carry out realistic 3D simulations of surface convection…

天体物理学 · 物理学 2009-11-13 Remo Collet , Martin Asplund , Regner Trampedach

The discrepancy between cosmological Li abundance inferred from Population II dwarf stars and that derived from WMAP/BBNS is still far from being solved.We investigated, as an alternative route, the use of Li abundances in Population II…

太阳与恒星天体物理 · 物理学 2015-05-30 A. Mucciarelli , M. Salaris , P. Bonifacio

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…

We present self-consistent calculations coupling numerical hydrodynamics simulations of collapsing pre-stellar cores and stellar evolution models of accreting objects. We analyse the main impact of consistent accretion history on the…

太阳与恒星天体物理 · 物理学 2016-12-21 I. Baraffe , V. G. Elbakyan , E. I. Vorobyov , G. Chabrier

The study of Li phenomena in red clump (RC) stars can give us a deeper understanding of the structure and evolution of stars. \citet{2022ApJ...933...58C} explained the RC Li abundance distributions naturally using only standard post main…

太阳与恒星天体物理 · 物理学 2024-03-05 Xuefeng Li , Jianrong Shi , Yan Li , Hongliang Yan , Jinghua Zhang

We report the statistical properties of stars, brown dwarfs and multiple systems obtained from the largest hydrodynamical simulation of star cluster formation to date that resolves masses down to the opacity limit for fragmentation (a few…

天体物理学 · 物理学 2010-04-29 Matthew Bate

Realistic 3-dimensional (3D), radiative hydrodynamical surface convection simulations of the metal-poor halo stars HD 140283 and HD 84937 have been performed. Due to the dominance of adiabatic cooling over radiative heating very low…

天体物理学 · 物理学 2007-05-23 M. Asplund , AA. Nordlund , R. Trampedach , R. F. Stein

Low mass stars (< 2-2.5 M_sun) exhibit, at all the stages of their evolution, signatures of processes that require challenging modeling beyond the standard stellar theory. In this paper we focus on their peculiarities while they climb the…

天体物理学 · 物理学 2016-08-30 Corinne Charbonnel , Ana Palacios

We reanalyze the problem of Li abundances in red giants of nearly solar metallicity. After an outline of the problems affecting our knowledge of the Li content in low-mass stars (M<3Mo), we discuss deep-mixing models for the RGB stages…

太阳与恒星天体物理 · 物理学 2015-05-28 S. Palmerini , S. Cristallo , M. Busso , C. Abia , S. Uttenthaler , L. Gialanella , E. Maiorca

We study lithium depletion in low-mass and solar-like stars as a function of time, using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope. This new form is motivated by…

太阳与恒星天体物理 · 物理学 2017-08-16 I. Baraffe , J. Pratt , T. Goffrey , T. Constantino , D. Folini , M. V. Popov , R. Walder , M. Viallet

We present preliminary results from Smooth Particle Hydrodynamics (SPH) simulations of common envelope evolution. We qualitatively compare the interaction between a 0.9M red giant with two different companion masses: a 0.05M brown dwarf and…

天体物理学 · 物理学 2007-11-05 Steven Diehl , Chris Fryer , Falk Herwig

We have undertaken a series of hydrodynamic + N-body simulations in order to explore the properties of young stars. Our results suggest that the IMF may be sensitive to environment in its substellar region, with more brown dwarfs being…

天体物理学 · 物理学 2007-05-23 Eduardo Delgado-Donate , Cathie Clarke

Investigating the apparent anomalies in lithium (Li) surface abundance observed in the Sun and young stellar globular clusters holds significant promise for advancing our understanding of the mechanisms influencing Li depletion. This study…

太阳与恒星天体物理 · 物理学 2026-03-11 R. Caballero Navarro , A. García Hernández , J. C. Suárez

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…

We present FLAMES/GIRAFFE spectroscopy obtained at the Very Large Telescope (VLT). Using these observations we have been able for the first time to observe the Li I doublet in the Main Sequence stars of a Globular Cluster. We also observed…

(Abridged) Stars more massive than $20-30M_{\odot}$ are so luminous that the radiation force on the cooler, more opaque outer layers can balance or exceed the force of gravity. These near or super-Eddington outer envelopes represent a long…

太阳与恒星天体物理 · 物理学 2018-09-28 Yan-Fei Jiang , Matteo Cantiello , Lars Bildsten , Eliot Quataert , Omer Blaes , James Stone

We report the statistical properties of stars, brown dwarfs and multiple systems obtained from the largest radiation hydrodynamical simulation of star cluster formation to date that resolves masses down to the opacity limit for…

太阳与恒星天体物理 · 物理学 2015-05-30 Matthew R. Bate
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