2024/02/22 by M. P. Roriz, Roriz, M. P., N. Holanda +11 · 1 citation
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2402.14709
openalex publication_date 2024/02/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A classical Local Thermodynamic Equilibrium analysis, based on high-resolution spectroscopic data, is performed for a sample of three potential barium dwarf candidates and one star already recognized as such. We derived their atmospheric parameters, estimated their masses and luminosities, and determined chemical abundances for a set of 21 elements, including CNO. Some elemental abundances are derived for the first time in HD~15096, HD~37792, and HD~141804. The program stars are dwarfs/subgiants with metallicities typical of disc stars, exhibiting moderate carbon enhancements, with \rm[C/Fe] ratios ranging from +0.29 to +0.66 dex, and high levels of slow neutron-capture (s-process) elements, with \rm[s/Fe]\gtrsim +1.0~dex. As spectroscopic binaries, their peculiarities are attributable to mass transfer events. The observed neutron-capture patterns of were individually compared with two sets of s-process nucleosynthesis models (Monash and \sc fruity), yielding dilution factors and masses estimates for the former polluting Asymptotic Giant Branch stars. Low-mass (\lesssim 3.0~\rmM\odot) models successfully reproduce the observations. In addition, we estimated mean neutron exposures of the order of 0.6 -- 0.7 mb-1 for the s-processed material observed in their envelopes. Applying an empirical initial-final mass relation, we constraint in ∼ 0.7 \textrmM\odot the mass of their dim white-dwarf companions. Moreover, our kinematic study revealed that the program stars are members of the thin disk, with probabilities greater than 70%. Hence, we identified HD~15096 and HD~37792 as new barium dwarfs and confirmed that HD~141804 is a barium dwarf. Thus, the number of barium dwarfs identified in the literature from high-resolution spectroscopy increases to 71 objects.