Current theory regarding heavy element nucleosynthesis in metal-poor environments states that the r-process would be dominant. The star HD140283 has been the subject of debate after it appeared in some studies to be dominated by the s-process. We provide an independent measure of the Ba isotope mixture in HD140283 using an extremely high quality spectrum and an extensive chi^2 analysis. We exploit hyperfine splitting of the BaII 4554 Å and 4934 Å resonance lines in an effort to constrain the isotope ratio in 1D LTE. Using the code ATLAS in conjunction with KURUCZ06 model atmospheres we analyse 93 Fe lines to determine the star's macroturbulence. With this information we construct a grid of Ba synthetic spectra and, using a χ^2 code, fit these to our observed data to determine the isotopic ratio, fodd, which represents the ratio of odd to even isotopes. We also analyse the Eu lines. We set a new upper limit of the rotation of HD140283 at vsin{i}\leq3.9\kms, a new upper limit on [Eu/H] < -2.80 and abundances [Fe/H] = -2.59\pm0.09, [Ba/H] = -3.46\pm0.11. This leads to a new lower limit on [Ba/Eu] > -0.66. We find that, in the framework of a 1D LTE analysis, the isotopic ratios of Ba in HD140283 indicate fodd=0.02\pm0.06, a purely s-process signature. This implies that observations and analysis do not validate currently accepted theory. We speculate that a 1D code, due to simplifying assumptions, is not adequate when dealing with observations with high levels of resolution and S/N because of the turbulent motions associated with a 3D stellar atmosphere. New approaches to analysing isotopic ratios, in particular 3D hydrodynamics, need to be considered when dealing with the levels of detail required to properly determine them. However published 3D results exacerbate the disagreement between theory and observation.
The nucleosynthesis of Ba in the Early Universe. Constraints from elemental abundances and isotopic ratios
INAF – Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Dipartimento di Fisica, Sezione di Astronomia, Università di Trieste（的里雅斯特大学物理系天文学科）；INAF - Osservatorio Astronomico d'Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；INFN - Sezione di Perugia（意大利国家核物理研究院佩鲁贾分部）；Universidad de Valladolid（巴利亚多利德大学）
A Near-Infrared and Optical Study of NGC 5822: An Open Cluster Hosting Barium-stars and Lithium-Enriched Giant Stars
Observatório Nacional（巴西国家天文台）；Universidade Federal de Sergipe（塞尔希培联邦大学）；Malmö University（马尔默大学）；Nordic Optical Telescope（北欧光学望远镜）；Universidad Nacional de Córdoba – Observatorio Astronómico de Córdoba（科尔多瓦国立大学–科尔多瓦天文台）；Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（阿根廷国家科学研究委员会）
Unveiling the nature of barium stars. I. Asteroseismic masses and the evolutionary link between Ba dwarfs and giants
Indian Institute of Astrophysics（印度天体物理研究所）；Pondicherry University（本地治里大学）；School of Physics and Astronomy, Monash University（蒙纳士大学物理与天文学院）；CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台光学天文重点实验室）；Department of Physics, Indian Institute of Technology Jammu（詹姆印度理工学院物理系）
