The abundances of heavy elements in BL138 – red giant of local group fornax dwarf spheroidal galaxy

  • V.F. Gopka
  • A.V. Yushchenko
  • V.A. Yushchenko
  • A.V. Shavrina
  • S.M. Andrievsky
  • Y. Jeong
  • E.P. Shereta


Using the spectrum obtained with FLAMES/GIRAFFE multi-object spectrograph installed at ESO VeryLarge Telescope we investigated the absorption lines of heavy elements in the spectrum of BL138. Thisred giant star belongs to one of the Local Group members – Fornax dwarf spheroidal galaxy. Theabundances of 12 stable chemical elements, namely Y, Zr, Nb, Mo, Ru, La, Ce, Pr, Nd, Eu, Dy, Er, Lu,and Hf. The abundance of radioactive elements Ac and Th are also investigated. The analysis of theseabundances and also previously published investigation of BL138 allowed claiming that the distributionof abundances is different from that in the solar photosphere. The signs of r-process in the abundancepattern of BL138 are not important. The production of elements from barium to hafnium can be explainedby s-process. The abundances of elements from yttrium to ruthenium are lower than it can be expected inthe case of s-process synthesis. That is why it can be expected that several nuclear processes took place inthe synthesis of these elements. The possibility of detection the actinium absorption line in the spectrumof BL138 clearly indicate the possibility of physical process which results in continuous production ofactinium in the atmosphere of BL138. The actinium abundance can be close to logN(Ac)=1.9. It can bethe result of hydrogen accretion from interstellar medium on stellar photosphere. The trends ofabundances with second ionization potentials of corresponding chemical elements, and also by theemissions in the profiles of hydrogen H α line confirm this identification.
How to Cite
GOPKA, V.F. et al. The abundances of heavy elements in BL138 – red giant of local group fornax dwarf spheroidal galaxy. Physical Sciences and Technology, [S.l.], v. 5, n. 1, p. 70-78, aug. 2018. ISSN 2409-6121. Available at: <>. Date accessed: 19 mar. 2019. doi:
Nuclear Physics and Related Techology