Chemical Composition and Photometry of BE Lyncis

Kim, Chulhee; Yushchenko, A. V.; Kim, S.-L.; Jeon, Young‐Beom; Kim, Chun-Hwey

doi:10.1086/665943

Cited by 3 publications

(1 citation statement)

References 40 publications

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“…Notably, the theory of accretion from the interstellar medium has not been developed in detail. The observational results published by Böhm-Vitense ( 2006), Yushchenko et al (2015), and Jeong et al (2019) for different groups of stars and by Kim et al (2012), Kang et al (2012Kang et al ( , 2013, Jeong et al (2017Jeong et al ( , 2019, Yushchenko et al (2017a,b), and Yushchenko et al (2020) for individual stars, as well as this investigation, suppose that interstellar gas accretion should be considered for stars over a wide range of effective temperatures.…”

Section: Discussionsupporting

confidence: 56%

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

Yushchenko¹,

Kim²,

Jeong³

et al. 2021

Journal of Astronomy and Space Sciences

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The dependencies of the chemical element abundances in stellar atmospheres with respect to solar abundances on the second ionization potentials of the same elements were investigated using the published stellar abundance patterns for 1,149 G and K giants in the Local Region of the Galaxy. The correlations between the relative abundances of chemical elements and their second ionization potentials were calculated for groups of stars with effective temperatures between 3,764 and 7,725 K. Correlations were identified for chemical elements with second ionization potentials of 12.5 eV to 20 eV and for elements with second ionization potentials higher than 20 eV. For the first group of elements, the correlation coefficients were positive for stars with effective temperatures lower than 5,300 K and negative for stars with effective temperatures from 5,300 K to 7,725 K. The results of this study and the comparison with earlier results for hotter stars confirm the variations in these correlations with the effective temperature. A possible explanation for the observed effects is the accretion of hydrogen and helium atoms from the interstellar medium.

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Section: Discussionsupporting

confidence: 56%

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

Yushchenko¹,

Kim²,

Jeong³

et al. 2021

Journal of Astronomy and Space Sciences

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THE CHEMICAL COMPOSITION OFρPUPPIS AND THE SIGNS OF ACCRETION IN THE ATMOSPHERES OF B–F-TYPE STARS

Yushchenko

Gopka

Kang

et al. 2015

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We investigated the chemical composition of ρ Pup using high-resolution spectral observations taken from the Very Large Telescope and the IUE archives and also spectra obtained at the 1.8 m telescope of the Bohyunsan observatory in Korea. The abundances of 56 chemical elements and the upper limits of Li and Be abundances were determined. The abundance pattern of ρ Pup was found to be similar to that of Am-type stars. The possibility of the influence of the accretion of interstellar gas and dust on the abundance patterns of B-F-type stars is discussed. The plots of the relative abundances of chemical elements in the atmospheres of ρ Pup and δ Sct versus the second ionization potentials of these elements show the correlations. The discontinuities at 13.6 and 24.6 eV-the ionization potentials of hydrogen and helium, respectively, are also exhibited in these plots. These discontinuities can be explained by interaction of the atoms of interstellar gas, mainly hydrogen and helium atoms, with the atoms of stellar photospheres (so-called charge-exchange reactions). Note that only the jumps near 13.6 and 24.6 eV were pointed out in previous investigations of relative abundances versus the second ionization potentials for Am-type stars. The dependencies of the relative abundances of chemical elements on the second ionization potentials of these elements were investigated using the published abundance patterns of B-F-type stars. The correlations of relative and absolute abundances of chemical elements, second ionization potentials, and projected rotational velocities are clearly detected for stars with effective temperatures between 7,000 and 12,000 K. If the correlation of relative abundances and second ionization potentials can be explained by the accretion of interstellar gas on the stellar surfaces, the investigation of these correlations can provide valuable information on the density and velocities of interstellar gas in different regions of the Galaxy and also on the influence of this phenomenon on stellar evolution. The dependencies of the relative abundances of chemical elements on the condensation temperatures of these elements were also found in the atmospheres of ρ Pup, δ Sct, and other B-F-type stars. Ten possible λ Boo-type stars were detected. The effective temperatures of these objects are between 10,900 and 14,000 K.

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Catalogue and properties of δ Scuti stars in binaries

Liakos

Niarchos

2016

Mon. Not. R. Astron. Soc.

100

104

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The catalogue contains 199 confirmed cases of binary systems containing at least one pulsating component of δ Sct type. The sample is divided into subgroups in order to describe the properties and characteristics of the δ Sct type stars in binaries according to their Roche geometry. Demographics describing quantitatively our knowledge for these systems as well as the distributions of their pulsating components in the Mass-Radius, Colour-Magnitude and Evolutionary Status-Temperature diagrams are presented and discussed. It is shown that a threshold of ∼13 days of the orbital period regarding the influence of binarity on the pulsations is established. Finally, the correlations between the pulsation periods and the orbital periods, evolutionary status, and companion's gravity influence are updated based on the largest sample to date.

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Chemical Composition and Photometry of BE Lyncis

Cited by 3 publications

References 40 publications

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

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

THE CHEMICAL COMPOSITION OFρPUPPIS AND THE SIGNS OF ACCRETION IN THE ATMOSPHERES OF B–F-TYPE STARS

Catalogue and properties of δ Scuti stars in binaries

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