Abundances of neutron capture elements in dwarf stars of the Solar neighborhood located towards the north celestial pole
| Main Authors: | Carlos Viscasillas Vázquez, Gražina Tautvaišienė, Šarūnas Mikolaitis, Vilius Bagdonas, Renata Minkevičiūtė, Arnas Drazdauskas, Edita Stonkutė, Lukas Klebonas, Erika Pakštienė, Rimvydas Janulis |
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| Format: | Proceeding poster Journal |
| Bahasa: | eng |
| Terbitan: |
, 2019
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/2634527 |
Daftar Isi:
- Chemical compositions of stars provide us with unique information about their nucleosynthesis processes and the chemical enrichment of the Galaxy. Elements heavier than iron cannot be produced by nuclear fusion and require capturing neutrons by lighter elements. However, the conditions and environment needed for such processes are still relatively uncertain. While it is well established that asymptotic giant branch stars play an important role in the production of s-process chemical elements, recent studies show that their contribution was underestimated. As dwarf stars have a very long, relatively stable lives and do not show any substantial stellar evolution; their surface abundances are very helpful for studying the environment and time in which they were formed. Our aim was to determine abundance patterns of neutron-capture elements and probe the evolution of the Milky Way stellar disc. For this purpose we used spectra obtained with a Vilnius University Echelle Spectrograph and 1.65 m telescope for a sample of almost 300 F and G spectral type bright (V < 8 mag) dwarf stars (logg > 3.5) in two nearby fields towards the north celestial pole direction, with metallicities between -0.7 < [Fe/H] < +0.5. The method used for the analysis of chemical abundances is based on the spectral synthesis using the code TurboSpectrum combined with the MARCS stellar atmospheres models. We provide the chemical composition and time evolution for Sr II; Y II; Zr I; Zr II; Ba II; La II; Ce II; Nd II; Pr II; Sm II; and Eu II at different mean Galactocentric distances. For majority of the stars investigated in this work, it is the first time that abundances of neutron-capture elements were determined. The investigated stars were used to trace how the s-process was influencing the production of n-capture elements during the evolution of the Galactic thin disc.