HD 121135: FEATURES OF ITS CHEMICAL COMPOSITION

Автор(и)

  • T. Mishenina Odessa National University, Ukraine
  • I. Usenko Odessa National University, Mykolaiv Astronomical Observatory, Ukraine
  • A. Kniazev South African Astronomical Observatory, South Africa
  • V. Kovtyukh Odessa National University,, Ukraine

DOI:

https://doi.org/10.18524/1810-4215.2020.33.216277

Ключові слова:

stars, abundances – stars, atmospheres – stars, Population II, individual HD 121135

Анотація

Low metallicity star HD121135 ([Fe/H] =
-1.5) have been investigated spectroscopically. Its atmos-
pheric parameters and elemental abundances have been
determined, including elements of neutron (n-) capture
processes, which are the keys in the study of early Galaxy
enrichment. Na, Mg, Ni, Co, Sr, Y, Zr, Mo, Ba, La, Ce, Pr,
Sm, Eu, Gd, Dy, Ho, Os, Th abundances were calculated
using the synthetic spectrum method, factoring in the hy-
perfine structure (HFS) for the Eu II lines. Si, Ca, Sc abun-
dances were determined using the equivalent widths of
their lines. The carbon content was computed by the molec-
ular synthesis fitting for the region of CH (4300-4330 ÅÅ).
For the abundances determinations of C, Na, Mg, Ba, and
Th the NLTE corrections have been applied.
We have determined for the first time the abundances
of several n-capture elements and found that the behaviors
of these elements do not show a significant trend with
increasing atomic number. The elements ratios of [Eu/Fe]
= 0.06, [Ba/Eu] = 0.13, [Sr/Ba] = - 0.05 do not support the
HD121135 status as a r-process enrichment star. We have
obtained the thorium abundance [Th/Fe] = 0.26. The car-
bon content confirms the effect of canonical additional
mixing in this star.

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Опубліковано

2020-11-14

Номер

Розділ

Астрофізика (зоряні атмосфери, взаємодіючі подвійні системи, змінні зорі)