We provide measurements of the Ba isotopic fractions for five metal-poor stars derived with an LTE analysis using 1D model stellar atmospheres. We use high resolution (Requiv{lambda}/Delta{lambda}=90000-95000), very high signal-to-noise (S/N>500) spe
ctra to determine the fraction of odd Ba isotopes (fodd) by measuring subtle asymmetries in the profile of the Ba ii line at 4554 {AA}. We also use two different macroturbulent broadening techniques, Gaussian and radial-tangential, to model the Fe lines of each star, and propagate each technique to model macroturbulent broadening in the Ba 4554 {AA} line. We conduct a 1D non-LTE (NLTE) treatment of the Fe lines in the red giant HD122563 and the subgiant HD140283 in an attempt to improve the fitting. We determine [Ba/Eu] ratios for the two giants in our study, HD122563 and HD88609, which can also be used to determine the relative contribution of the s- and r-processes to heavy-element nucleosynthesis, for comparison with fodd. We find fodd for HD122563, HD88609 and HD84937, BD+26circ3578 and BD-04circ3208 to be -0.12pm0.07, -0.02pm0.09, and -0.05pm0.11, 0.08pm0.08 and 0.18pm0.08 respectively. This means that all stars examined here show isotopic fractions more compatible with an s-process dominated composition. The [Ba/Eu] ratios in HD122563 and HD88609 are found to be -0.20pm0.15 and -0.47pm0.15 respectively, which indicate instead an r-process signature. We report a better statistical fit to the majority of Fe profiles in each star when employing a radial-tangential broadening technique during our 1D LTE investigation. We have shown that, from a statistical point of view, one must consider using a radial-tangential broadening technique rather than a Gaussian one to model Fe line macroturbulences when working in 1D. No improvement to Fe line fitting is seen when employing a NLTE treatment.
One of the most important factors in determining the stellar lithium abundance is the effective temperature. In a previous study by the authors, new effective temperatures Teff for sixteen metal-poor halo dwarfs were derived using a local thermodynam
ic equilibrium (LTE) description of the formation of Fe lines. This new Teff scale reinforced the discrepancy. For six of the stars from our previous study we calculate revised temperatures using a non-local thermodynamic equilibrium (NLTE) approach. These are then used to derive a new mean primordial lithium abundance in an attempt to solve the lithium discrepancy. Using the code MULTI we calculate NLTE corrections to the LTE abundances for the Fe I lines measured in the six stars, and determine new Teffs. We keep other physical parameters, i.e. log g, [Fe/H] and xi, constant at the values calculated in Paper I. With the revised Teff scale we derive new Li abundances. We compare the NLTE values of Teff with the photometric temperatures of Ryan et al. (1999, ApJ, 523, 654), the infrared flux method (IRFM) temperatures of Melendez & Ramirez (2004, ApJ, 615, 33), and the Balmer line wing temperatures of Asplund et al. (2006, ApJ, 644, 229). We find that our temperatures are hotter than both the Ryan et al. and Asplund et al. temperatures by typically ~ 110 K - 160 K, but are still cooler than the temperatures of Melendez & Ramirez by typically ~ 190 K. The temperatures imply a primordial Li abundance of 2.19 dex or 2.21 dex, depending on the magnitude of collisions with hydrogen in the calculations, still well below the value of 2.72 dex inferred from WMAP + BBN. We discuss the effects of collisions on trends of 7Li abundances with [Fe/H] and Teff, as well as the NLTE effects on the determination of log g through ionization equilibrium, which imply a collisional scaling factor SH > 1 for collisions between Fe and H atoms.
