Spectral observations using a BTA telescope of chemically peculiar stars in the spectral region near the Li I (6708 Å) resonance doublet

Polosukhina, N. S.; Шаврина, А. В.; Драке, Н. А.; Kudryavtsev, D. O.; Smirnova, M.

doi:10.3103/s0190271710010109

Cited by 2 publications

(2 citation statements)

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“…For HD 97394 we obtained an almost solar abundance of Fe while Cr is enhanced by 2 dex and Sc and Ti are enhanced by 1 dex compared to the Sun. After being debated for several decades, the presence of lithium in a number of (cool) Ap stars has now been convincingly established (Polosukhina et al 1999, 2010; Kochukhov 2008). In the spectrum of HD 97394 we found a line in the region of the Li i doublet at 6707.761 and 6707.912 Å that is partly blended with a stronger Ce ii line 6708.099 Å.…”

Section: Analysis Of the Observational Datamentioning

confidence: 99%

HD 97394: a magnetic Ap star with high cerium overabundance★

Elkin

Kurtz

Mathys

2011

Monthly Notices of the Royal Astronomical Society

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We report a spectroscopic analysis of the chemically peculiar Ap star HD 97394. The stellar spectrum is rich in lines of rare earth elements with large overabundances, especially cerium, gadolinium and europium. Enhancement of the abundances of these rare earths shows this star to be one of the most peculiar stars. Very large overabundances were found for lines of Ce iii and Eu iii. Abundances obtained from second ionization lines of Nd, Ce and Eu are about 2 dex higher than for those of the first ionization. From partially split Zeeman components of the Fe ii 6149.258 Å line and from synthetic modelling, a global magnetic field of 3.1 kG was measured. We tested for pulsation of the star with high time resolution spectroscopy obtained with the ESO Very Large Telescope. We place an upper limit to any pulsation amplitude of 30–40 m s−1 for individual lines of rare earth elements, of 10–20 m s−1 for the combination of several lines, and of 6–10 m s−1 for cross‐correlation over large spectral bands.

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Section: Analysis Of the Observational Datamentioning

confidence: 99%

HD 97394: a magnetic Ap star with high cerium overabundance★

Elkin

Kurtz

Mathys

2011

Monthly Notices of the Royal Astronomical Society

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“…As reported by Swaczyna et al (2019), after charge exchange with interstellar neutral atoms a number of solar wind He 2+ turn into He + , which become an important constituent of the solar wind. Lithium atoms which originated in the Big Bang are one of the most abundant elements in the universe after hydrogen and helium (Polosukhina et al 2010;Polosukhina & Shavrina 2007;Ramírez et al 2012). Furthermore, collisions of multiply charged ions with lithium atoms can also be 210-2 X.-X.…”

Section: Introductionmentioning

confidence: 99%

Charge transfer and excitation processes in low energy collisions of He⁺ ions with Li atoms

Wang

Peng

et al. 2021

Res. Astron. Astrophys.

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Electron capture between solar wind ions and neutral species has contributed to the understanding of X-ray production from solar system bodies. The charge transfer and excitation processes in solar wind ions of He+(1s) colliding with Li(1s 22s) atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling (QMOCC) method with impact energies of 0.003–2 keV amu−1. Comparisons of cross sections from single- and multi-configurational calculations for a self-consistent field (SCF and MCSCF) process are carried out. Results show that the dominant reaction channels are He(1s2l 1,3L) + Li+(1s 2 1S). Good consistency is found among present total and state-selective charge transfer and excitation cross sections with other theoretical and experimental data in the same energy region. Due to the differences between coupling matrix elements in high-energy states, the charge transfer cross sections calculated from SCF and MCSCF split slightly as E > 0.4 keV amu−1. Weak Stueckelberg oscillations for charge transfer appear in the present work. In addition, the differences of cross sections for electron excitation to Li(1s 22p) in the singlet/triplet molecular states with He+(1s) are much smaller than those of charge transfer processes because of the similar energy gaps from Li(1s 22p) to the ground state in singlet/triplet states in the large R region.

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Spectral observations using a BTA telescope of chemically peculiar stars in the spectral region near the Li I (6708 Å) resonance doublet

Cited by 2 publications

References 5 publications

HD 97394: a magnetic Ap star with high cerium overabundance★

HD 97394: a magnetic Ap star with high cerium overabundance★

Charge transfer and excitation processes in low energy collisions of He⁺ ions with Li atoms

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Spectral observations using a BTA telescope of chemically peculiar stars in the spectral region near the Li I (6708 Å) resonance doublet

Cited by 2 publications

References 5 publications

HD 97394: a magnetic Ap star with high cerium overabundance★

HD 97394: a magnetic Ap star with high cerium overabundance★

Charge transfer and excitation processes in low energy collisions of He+ ions with Li atoms

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Charge transfer and excitation processes in low energy collisions of He⁺ ions with Li atoms