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Magellanic Clouds Cepheids: Thorium Abundances
정연철,Alexander V. Yushchenko,Vira F. Gopka,Volodymyr O. Yushchenko,Valery V. Kovtyukh,Svetlana V. Vasil’eva 한국우주과학회 2018 Journal of Astronomy and Space Sciences Vol.35 No.1
The analysis of the high-resolution spectra of 31 Magellanic Clouds Cepheid variables enabled the identification of thorium lines. The abundances of thorium were found with spectrum synthesis method. The calculated thorium abundances exhibit correlations with the abundances of other chemical elements and atmospheric parameters of the program stars. These correlations are similar for both Clouds. The correlations of iron abundances of thorium, europium, neodymium, and yttrium relative to the pulsational periods are different in the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), namely the correlations are negative for LMC and positive or close to zero for SMC. One of the possible explanations can be the higher activity of nucleosynthesis in SMC with respect to LMC in the recent several hundred million years.
Alexander Yushchenko,Dmytry Doikov,Sergei Andrievsky,Yeuncheol Jeong,Volodymyr Yushchenko,Pakakaew Rittipruk,Valery Kovtyukh,Aizat Demessinova,Vira Gopka,Alexander Raikov,Kyung Sook Jeong 한국우주과학회 2022 Journal of Astronomy and Space Sciences Vol.39 No.4
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.
Yushchenko, Alexander,Doikov, Dmytry,Andrievsky, Sergei,Jeong, Yeuncheol,Yushchenko, Volodymyr,Rittipruk, Pakakaew,Kovtyukh, Valery,Demessinova, Aizat,Gopka, Vira,Raikov, Alexander,Jeong, Kyung Sook The Korean Space Science Society 2022 Journal of astronomy and space sciences Vol.39 No.4
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.