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Thermonuclear burning on the surface of accreting neutron stars is observed to stabilize at accretion rates almost an order of magnitude lower than theoretical models predict. One way to resolve this discrepancy is by including a base…

Solar and Stellar Astrophysics · Physics 2015-06-22 Michael Zamfir , Andrew Cumming , Caroline Niquette

New fibre spectroscopy and radial velocities from the WIYN telescope are used to measure photospheric lithium in 242 high-probability, zero-age-main-sequence (ZAMS) F- to K-type members of the rich cluster M35. Combining these with…

Solar and Stellar Astrophysics · Physics 2020-10-21 R. D. Jeffries , R. J. Jackson , Qinghui Sun , Constantine P. Deliyannis

We evaluated the bias and variability on the fitted age and convective core overshooting parameter for evolved binary stars accounting for observational and internal uncertainties. We considered a binary system composed of a 2.50 $M_{\sun}$…

Solar and Stellar Astrophysics · Physics 2018-07-18 G. Valle , M. Dell'Omodarme , P. G. Prada Moroni , S. Degl'Innocenti

Recently, we studied the chemical evolution of lithium in the thin disc of the Milky Way. We found that the best agreement with the observed Li abundances in the thin disc is obtained considering novae as the main source of lithium. We…

Solar and Stellar Astrophysics · Physics 2020-04-15 G. Cescutti , P. Molaro , X. Fu

M-dwarf stars provide very favourable conditions to find habitable worlds beyond our solar system. The estimation of the fundamental parameters of the transiting exoplanets rely on the accuracy of the theoretical predictions for radius and…

Solar and Stellar Astrophysics · Physics 2019-06-12 Santi Cassisi , Maurizio Salaris

We provide *lambda*6708 Li 1 measurements in 37 metal-poor stars, most of which are poorly-studied or have no previous measurements, from high-resolution and high-S/N spectroscopy obtained with the McDonald Observatory 2.1m and 2.7m…

Solar and Stellar Astrophysics · Physics 2015-06-03 Marc Schaeuble , Jeremy R. King

We want to investigate how planet formation is imprinted on stellar surface composition using up-to-date stellar evolution models. We simulate the evolution of pre-main-sequence stars as a function of the efficiency of heat injection during…

Solar and Stellar Astrophysics · Physics 2018-10-24 Masanobu Kunitomo , Tristan Guillot , Shigeru Ida , Taku Takeuchi

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…

Astrophysics · Physics 2011-05-23 Luca Pasquini , Paolo Molaro

Motivated by the recent report of a $^6$Li detection in the atmosphere of HD~84937, we couple stellar evolution calculations with light isotope production via stellar flares. We find that as a consequence of their small convective envelope…

Astrophysics · Physics 2009-10-22 C. P. Deliyannis , R. A. Malaney

Our aim was to determine the initial Li content of two clusters of similar metallicity but very different ages, the old open cluster NGC 2243 and the metal-rich globular cluster NGC 104. We compared the lithium abundances derived for a…

Solar and Stellar Astrophysics · Physics 2021-09-08 Misa Aoki , Francesca Primas , Luca Pasquini , Achim Weiss , Maurizio Salaris , Daniela Carollo

(Abridged) We contribute to our understanding of the evolution of young intermediate-mass stars by providing a comprehensive analysis of their lithium (Li) content. A sample of 71 intermediate-mass T Tauri (IMTT) and Herbig stars within the…

Abundances of lithium, carbon, and oxygen have been derived using spectral synthesis for a sample of 249 bright F, G, and K Northern Hemisphere dwarf stars from the high-resolution spectra acquired with the VUES spectrograph at the Moletai…

Of all the light elements, lithium is the most sensitive indicator of stellar evolution. This review discusses current data on the abundance of lithium in the atmospheres of A-, F-, G-, and K-stars of different types, as well as the…

Solar and Stellar Astrophysics · Physics 2017-01-23 L. S. Lyubimkov

The effective temperature, one of the most fundamental atmospheric parameters of a star, can be estimated using various methods, and here we focus on the method using line-depth ratios (LDRs). This method combines low- and high-excitation…

Absorption features in stellar atmospheres are often used to calibrate photocentric velocities for kinematic analysis of further spectral lines. The Li feature at $\sim$ 6708 {\AA} is commonly used, especially in the case of young stellar…

The determination of effective temperatures of very hot central stars (Teff>70000K) by model atmosphere analyses of optical H and He line profiles is afflicted with considerable uncertainty, primarily due to the lack of neutral helium…

Astrophysics · Physics 2007-05-23 K. Werner , J. L. Deetjen , S. Dreizler , T. Rauch , J. W. Kruk

We obtain lithium abundances for G and K stars in Blanco 1, an open cluster with an age similar to, or slightly younger than, the Pleiades. We critically examine previous spectroscopic abundance analyses of Blanco 1 and conclude that while…

Astrophysics · Physics 2009-10-30 R. D. Jeffries , D. J. James

Determinations of beryllium abundance in stars, together with lithium, provide a key tool to investigate the so far poorly understood extra-mixing processes at work in stellar interiors. We measured Be in three open clusters,complementing…

Astrophysics · Physics 2009-11-13 S. Randich , F. Primas , L. Pasquini , P. Sestito , R. Pallavicini

We have derived accurate and homogeneous Lithium abundances in 49 main sequence binary systems belonging to the Hyades Open Cluster by using a deconvolution method to determine individual magnitudes and colors for the primary and secondary…

Astrophysics · Physics 2007-05-23 D. Barrado y Navascues , J. R. Stauffer

(abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational…

Solar and Stellar Astrophysics · Physics 2015-05-06 Maurizio Salaris , Santi Cassisi
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