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We show by detailed model computation how much the Pre-Main Sequence (PMS) Lithium depletion depends on the treatment of over-adiabaticity, by taking advantage of the results of new models by Montalb\'an et al., which apply different…

Astrophysics · Physics 2009-11-10 F. D'Antona , J. Montalban

In spite of the great effort made in the last decades to improve our understanding of stellar evolution, significant uncertainties remain due to our poor knowledge of some complex physical processes that require an empirical calibration,…

Solar and Stellar Astrophysics · Physics 2015-06-22 Alessandro Bressan , Leo Girardi , Paola Marigo , Philip Rosenfield , Jing Tang

The Ly$\alpha$ emission has emerged as a powerful tool for probing diffuse gas within the large-scale structure of the universe. In this paper, we investigate cosmic Ly$\alpha$ emission by post-processing cosmological simulations from…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-02 Sung-Han Tsai , Ke-Jung Chen , Aaron Smith , Yi-Kuan Chiang

Francis & Hewett (1993) identified two 10-Mpc scale regions of the high redshift universe that were seemingly very overdense in neutral hydrogen. Subsequent observations showed that at least one of these gas-rich regions enveloped a cluster…

Astrophysics · Physics 2009-10-31 Paul J. Francis , Greg M. Wilson , Bruce E. Woodgate

Spectroscopically determined Li abundances of metal-poor turn-off dwarfs are known to be nearly constant (Spite plateau), but lower than the primordial value expected from the standard cosmological model. However, abundance determination by…

Solar and Stellar Astrophysics · Physics 2019-02-06 Yoichi Takeda

Energetic feedback processes during the formation of galaxy clusters may have heated and ionized a large fraction of the intergalactic gas in proto-cluster regions. When such a highly ionized hot ``super-bubble'' falls along the sightline…

Astrophysics · Physics 2009-06-25 Cien Shang , Arlin Crotts , Zoltán Haiman

We perform two-dimensional numerical simulations of core convection for zero-age-main-sequence stars covering a mass range from 3 $M_\odot$ to 20 $M_\odot$. The simulations are performed with the fully compressible time-implicit code MUSIC.…

Solar and Stellar Astrophysics · Physics 2023-01-18 I. Baraffe , J. Clarke , A. Morison , D. G. Vlaykov , T. Constantino , T. Goffrey , T. Guillet , A. Le Saux , J. Pratt

Recent solar abundance analyses (Asplund et al. 2004; Lodders 2003) revise downward the abundances of C, N, O, Ne, and Ar, which reduces the solar photospheric Z/X to 0.017, and Z to ~0.013. Solar models evolved with standard opacities and…

Astrophysics · Physics 2007-05-23 J. Guzik , L. S. Watson

Rotational velocity, lithium abundance, and the mass depth of the outer convective zone are key parameters in the study of the processes at work in the stellar interior, in particular when examining the poorly understood processes operating…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. D. do Nascimento , J. S. da Costa , J. R. De Medeiros

We present a spectroscopic study at high resolution, R~50,000, of 14 stars located on the main sequence, at the turn-off point and on the early subgiant branch in the cluster M67 in order to investigate its detailed chemical composition,…

Solar and Stellar Astrophysics · Physics 2015-06-17 Anna Önehag , Bengt Gustafsson , Andreas Korn

We have performed a new and homogeneous analysis of all the Li data available in the literature for main sequence stars (spectral-types from late F to K) in open clusters. In the present paper we focus on a detailed investigation of MS Li…

Astrophysics · Physics 2009-11-11 P. Sestito , S. Randich

Rate coefficients for inelastic collisions between Li and H atoms covering all transitions between the asymptotic states Li(2s,2p,3s,3p,3d,4s,4p,4d,4f)+H(1s) and Li^+ +H^- are presented for the temperature range 2000-8000 K based on recent…

Astrophysics · Physics 2009-11-10 P. S. Barklem , A. K. Belyaev , M. Asplund

We present an analytic calculation of the thermonuclear depletion of lithium in contracting, fully convective, pre-main sequence stars of mass M < 0.5 M_sun. Previous numerical work relies on still-uncertain physics (atmospheric opacities…

Astrophysics · Physics 2009-10-28 Lars Bildsten , Edward F. Brown , Christopher D. Matzner , Greg Ushomirsky

Precise studies on the Galactic bulge, halo, thick disk, and globular clusters require stellar models with alpha enhancement and various He contents. For this purpose we complement existing PARSEC (PAdova-TRieste Stellar Evolution Code)…

Solar and Stellar Astrophysics · Physics 2017-02-10 Xiaoting Fu

Precise Li abundances are determined for 54 giant stars mostly evolving across the Hertzsprung gap. We combine these data with rotational velocity and with information related to the deepening of the convective zone of the stars to analyse…

Astrophysics · Physics 2009-11-10 P. de Laverny , J. D. Jr do Nascimento , A. Lebre , J. R. De Medeiros

NGC288 is a globular cluster with a well-developed blue horizontal branch covering the u-jump that indicates the onset of diffusion. It is therefore well suited to study the effects of diffusion in blue horizontal branch (HB) stars. We…

Solar and Stellar Astrophysics · Physics 2014-05-21 S. Moehler , S. Dreizler , F. LeBlanc , V. Khalack , G. Michaud , J. Richer , A. V. Sweigart , F. Grundahl

Observations demonstrate that the surface abundance of $^7{\rm Li}$ in low-mass stars changes dramatically between the tip of the red giant branch and the red clump. This naturally suggests an association with the helium core flash, which…

Solar and Stellar Astrophysics · Physics 2020-09-30 Josiah Schwab

The Sun is an important calibrator for the theory of stellar structure and evolution. However, the accuracy of our solar evolution models is tightly linked to the physical ingredients that enter their computations. This include, amongst…

Solar and Stellar Astrophysics · Physics 2025-06-12 G. Buldgen , A. Noels , V. A. Baturin , J. Christensen-Dalsgaard , S. V. Ayukov , A. V. Oreshina , R. Scuflaire

Predicting diffusion coefficients in mixtures is crucial for many applications, as experimental data remain scarce, and machine learning (ML) offers promising alternatives to established semi-empirical models. Among ML models, matrix…

Machine Learning · Computer Science 2026-02-27 Zeno Romero , Kerstin Münnemann , Hans Hasse , Fabian Jirasek

We investigate a model of galaxy clusters in which the hot intracluster gas is efficiently heated by dynamical friction (DF) of galaxies. We allow for both subsonic and supersonic motions of galaxies and use the gravitational drag formula…

Astrophysics · Physics 2016-08-30 Woong-Tae Kim , Amr A. El-Zant , Marc Kamionkowski