The Possible Signs of Hydrogen and Helium Accretion from Interstellar Medium on the
            Atmospheres of F-K Giants in the Local Region of the Galaxy

Yushchenko, A. V.; Kim, Seung Hyun; Jeong, Yeuncheol; Demessinova, Aizat; Yushchenko, V. A.; Doikov, D. N.; Gopka, V. F.; Jeong, K. S.; Rittipruk, Pakakaew

doi:10.5140/jass.2021.38.3.175

Cited by 2 publications

(1 citation statement)

References 31 publications

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“…The chemical elements with SIPs between the two cutoffs, as well as the elements with SIPs less than the first cutoff and greater than the second cutoff, show positive correlations of relative abundances vs. SIPs in the above-mentioned three stars. Yushchenko et al (2015) and Yushchenko et al (2021) found similar correlations in the published observations of several hundred B-F type stars and disk red giants for chemical elements with SIPs between the two cutoffs and greater than the second cutoff. It was also shown that these correlations are dependent on the effective temperature and disappear for stars with convective energy transfer in their atmospheres.…”

Section: Interplay Of Several Scenariossupporting

confidence: 75%

The Chemical Composition of HD47536: A Planetary Host Halo Giant with Possible λ Bootis Features and Signs of Interstellar Matter Accretion

Yushchenko¹,

Doikov²,

Andrievsky³

et al. 2022

Journal of Astronomy and Space Sciences

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We investigated the chemical composition of the planetary host halo star HD47536 via high-resolution spectral observations recorded using a 1.5 meter Cerro Tololo Inter-American Observatory (CTIO) telescope (Chile). Furthermore, we determined the abundances of 38 chemical elements. Both light and heavy elements were overabundant compared to the iron group elements. The abundance pattern of HD47536 was similar to that of halo-type stars, with an enrichment of heavy elements. We analyzed the relationships between the relative abundances of chemical elements and their second ionization potentials and condensation temperatures. We demonstrated that the interplay of charge-exchange reactions owing to the accretion of interstellar matter and the gas-dust separation mechanism can influence the initial abundances and can be used to qualitatively explain the abundance patterns in the atmosphere of HD47536.

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Section: Interplay Of Several Scenariossupporting

confidence: 75%

The Chemical Composition of HD47536: A Planetary Host Halo Giant with Possible λ Bootis Features and Signs of Interstellar Matter Accretion

Yushchenko¹,

Doikov²,

Andrievsky³

et al. 2022

Journal of Astronomy and Space Sciences

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The Radioactive Elements in the Atmosphere of HD25354—Are They the Result of the Symmetric Decay of the Chemical Elements of the Island of Stability?

Yushchenko,

Gopka,

Yushchenko

et al. 2024

Galaxies

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In this research, we investigated the observed spectra of the hot peculiar star HD25354 with an effective temperature Teff = 12,800 K, identified the lines of radioactive chemical elements, including the elements with short decay time, and estimated the abundances of these elements. We tried to confirm or reject the existence of promethium lines and lines of other radioactive elements which were detected in previous investigations of this star and explain the physical mechanisms which are responsible for the synthesis of these elements in the stellar atmosphere. We used two high-dispersion spectra of HD25354 observed with the 2 m telescope of Terskol observatory with resolving power near R = 60,000, and a signal to noise ratio near 200. The spectrum of the star from the archive of the 1.93 m telescope of Haute-Provence observatory was also used. The observations were compared with synthetic spectra and the abundance of promethium was found using the best four lines of this element in the observed spectra: logN(Pm) = 5.84 ± 0.16 in the scale logN(H) = 12. It is comparable to the abundances of stable lanthanides in the atmosphere of this star. The abundance of thorium derived from two lines of double-ionized thorium is logN(Th) = 3.59 ± 0.15. The upper limits for technetium, radium, actinium, uranium, and americium abundances are found to be equal to 4.0, 3.0, 1.25, 3.5, and 4.0, respectively. Maybe the existence of promethium lines and lines of other unstable chemical elements in the spectra of HD25354, as well as the other stars of our Galaxy, Magellanic Clouds, and Fornax dwarf galaxy, can be explained by contamination of its atmosphere by the products of kilonova outburst and by symmetric decay of chemical elements with long decay times located at the island of stability (atomic numbers Z = 110–128) of transfermium elements. Maybe the decay of superheavy elements of the island of stability can be one of the reasons for the enhanced abundances of rare earth lanthanides in different types of stars.

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The Possible Signs of Hydrogen and Helium Accretion from Interstellar Medium on the Atmospheres of F-K Giants in the Local Region of the Galaxy

Cited by 2 publications

References 31 publications

The Chemical Composition of HD47536: A Planetary Host Halo Giant with Possible λ Bootis Features and Signs of Interstellar Matter Accretion

The Chemical Composition of HD47536: A Planetary Host Halo Giant with Possible λ Bootis Features and Signs of Interstellar Matter Accretion

The Radioactive Elements in the Atmosphere of HD25354—Are They the Result of the Symmetric Decay of the Chemical Elements of the Island of Stability?

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