Electric dipole transitions between low-lying levels in doubly ionized krypton, xenon, and radon

Eser, S.; Özdemir, Leyla

doi:10.1139/cjp-2017-0238

Cited by 3 publications

(3 citation statements)

References 32 publications

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“…The predicted Kr iii 3308.22, 3396.72 Å lines do not match observed lines. The alternative oscillator strengths for these two lines provided by Eser & Özdemir (2018) are even larger. These lines might require large shifts or have inaccurate oscillator strengths.…”

Section: Heavy Metalsmentioning

confidence: 94%

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Dorsch

Latour

Heber

et al. 2020

A&A

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Hot subdwarf stars of spectral types O and B represent a poorly understood phase in the evolution of low-mass stars, in particular of close compact binaries. A variety of phenomena are observed, which make them important tools for several astronomical disciplines. For instance, the richness of oscillations of many subdwarfs are important for asteroseismology. Furthermore, hot subdwarfs are among the most chemically peculiar stars known. Two intermediate He-rich hot subdwarf stars, LS IV–14°116 and Feige 46, are particularly interesting, because they show extreme enrichments of heavy elements such as Ge, Sr, Y, and Zr, which are strikingly similar in both stars. In addition, both stars show light oscillations at periods incompatible with standard pulsation theory and form the class of V366 Aqr variables. We investigated whether the similar chemical compositions extend to more complete abundance patterns in both stars and validate the pulsations in Feige 46 using its recent TESS light curve. High-resolution optical and near-ultraviolet spectroscopy are combined with non-local thermodynamical-equilibrium model atmospheres and synthetic spectra calculated with TLUSTY and SYNSPEC to consistently determine detailed metal abundance patterns in both stars. Many previously unidentified lines were identified for the first time with transitions originating from Ga III, Ge III-IV, Se III, Kr III, Sr II-III, Y III, Zr III-IV, and Sn IV, most of which have not yet been observed in any star. The abundance patterns of 19 metals in both stars are almost identical, light metals being only slightly more abundant in Feige 46, while Zr, Sn, and Pb are slightly less enhanced compared to LS IV–14°116. Both abundance patterns are distinctively different from those of normal He-poor hot subdwarfs of a similar temperature. The extreme enrichment in heavy metals of more than 4 dex compared to the Sun is likely the result of strong atmospheric diffusion processes that operate similarly in both stars while their similar patterns of C, N, O, and Ne abundances might provide clues to their as yet unclear evolutionary history. Finally, we find that the periods of the pulsation modes in Feige 46 are stable to better than Ṗ ≲ 10−8 s s−1. This is not compatible with Ṗ predicted for pulsations driven by the ɛ-mechanism and excited by helium-shell flashes in a star that is evolving, for example, onto the extended horizontal branch.

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Section: Heavy Metalsmentioning

confidence: 94%

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Dorsch

Latour

Heber

et al. 2020

A&A

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“…Because of the best results have been obtained according to CC correlations, only these results in here have been presented for six ions. Also we reported energies, lifetimes and electric dipole (E1) transition parameters, for these ions [16][17][18]. Other work values are indicated below the tables with a superscript lower case.…”

Section: Resultsmentioning

confidence: 99%

“…For Rn III and Rn IV, only Biémont and Quinet presented a study about forbidden transition parameters [15]. Also we reported electric dipole (E1) transition parameters, energies and lifetimes for these ions [16][17][18].…”

Section: Introductionmentioning

confidence: 97%

Electric quadrupole (E2) and magnetic dipole (M1) transitions for doubly and triply ionized krypton, xenon, and radon

Eser

Özdemir

2019

Can. J. Phys.

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We have reported the wavelengths, transition probabilities (or rates), oscillator strengths, and line strengths for forbidden transitions (electric quadrupole, E2, and magnetic dipole, M1) in doubly and triply ionized krypton, xenon, and radon using the general-purpose relativistic atomic structure package (GRASP). The results obtained from transitions between the levels of ground state configuration are in agreement with other available results in the literature. The data on forbidden transitions between high levels for these ions have been firstly presented in this work.

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Energies and electric dipole transitions for triply ionized Kr, Xe and Rn

Eser

Özdemir

2019

Indian J Phys

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Electric dipole transitions between low-lying levels in doubly ionized krypton, xenon, and radon

Cited by 3 publications

References 32 publications

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV–14°116 revisited

Electric quadrupole (E2) and magnetic dipole (M1) transitions for doubly and triply ionized krypton, xenon, and radon

Energies and electric dipole transitions for triply ionized Kr, Xe and Rn

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