Dysprosium III lines in the spectra of peculiar A and B stars

Aikman, G. C. L.; Cowley, C. R.; Crosswhite, H. M.

doi:10.1086/157342

Cited by 24 publications

(18 citation statements)

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“…As pointed out in the introduction, Nd III has been identified or mentioned as possibly present in a number of stars : HR 465, HD 51418, HD 200311 (Cowley 1976;Aikman et al 1979;Bidelman et al 1995), HD 192913 (Cowley & Crosswhite 1978Ryabchikova et al 1990), HD 101065 ) but the identification can be complicated by problems of different types. The identification of lanthanides in stars showing strong Si II lines is made difficult by the fact that only a few stars are known which show very sharp lines.…”

Section: Nd III In Stellar Spectramentioning

confidence: 99%

“…Doubly ionized neodymium (Nd III), which is expected to be the dominant species in hotter stars, has been identified in the spectra of some CP stars like HR 465, HD 51418 and HD 200311 (Cowley 1976;Aikman et al 1979;Bidelman et al 1995) and in the spectrum of HD 192913 and HD 43819, Bp stars of the Si subgroup (Cowley & Crosswhite 1978;Ryabchikova et al 1990). …”

Section: Introductionmentioning

confidence: 99%

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Measurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in Nd III

Zhang¹,

Svanberg²,

Palmeri

et al. 2002

A&A

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Abstract. Selective lifetime measurements by time-resolved laser-induced fluorescence spectroscopy for 5 levels belonging to the 4f 3 5d configuration of doubly ionized neodymium provide a first and useful experimental test of the relativistic Hartree-Fock calculations in this ion of astrophysical interest. As a consequence, the accuracy of the transition probabilities deduced in the present work is well assessed. These new data are expected to help astrophysicists in the future to refine the analysis of the composition of chemically peculiar stars which frequently show large overabundances of lanthanides when compared to the solar system standards.

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Section: Nd III In Stellar Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in Nd III

Zhang¹,

Svanberg²,

Palmeri

et al. 2002

A&A

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“…Nd iii has been observed in the spectrum of several CP stars having strong lines of Nd ii, for example HR 465, HD 51418, and HD 200311 (Cowley 1976;Aikman et al 1979); Nd ii and Nd iii have also been found in the Si star HD 192913 (Cowley & Crosswhite 1978;Ryabchikova et al 1990). We have previously reported on Nd iii in HR 6870 and γ Equ , and recent studies by our group have also revealed the strong presence of both Nd ii and Nd iii in the spectrum of HD 101065 (Cowley et al 2000), a rapidly oscillating Ap (roAp) star and arguably one of the most chemically bizarre objects in the Galaxy.…”

Section: Applications and Conclusionmentioning

confidence: 99%

Ab initio calculations of oscillator strengths and Landé factors for NdIII

Bord

2000

Astron. Astrophys. Suppl. Ser.

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Abstract. Theoretical calculations of oscillator strengths and Landé g-factors made with the Cowan code are presented for the rare-earth ion Nd iii. The emphasis is on transitions in the optical region of the spectrum. Comparisons of previous ab initio calculations of this type for other lanthanides (e.g., La ii, Ce iii, and Lu ii) with published experimental and theoretical data suggest that the accuracy of the log(gf ) values for individual transitions should be about ±0.15 dex in the absence of significant core polarization effects; the g-factors should be good to better than 5%, except in a few cases where term mixing is important. Applications of the data are made in the calculation of neodymium abundances in the atmospheres of the chemically peculiar stars HD 101065 ("Przybylski's star") and HD 122970.

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“…This need for accurate transition probabilities or f -values, frequently pointed out in astrophysics, has stimulated a variety of radiative lifetime measurements in neutral or singly ionized lanthanide atoms (Blagoev & Komarovskii 1994). However, according to the Saha equation, it is expected that the lanthanide elements are predominantly doubly ionized in the photosphere of the hotter CP stars (Aikman et al 1979). The very acute need for reliable atomic data in doubly ionized RE atoms has stimulated recent studies of the third lanthanide spectra by laser spectroscopy and also elaborate theoretical calculations (Zhang et al 2000(Zhang et al , 2001aWyart et al 1997;Biémont et al 1999Biémont et al , 2001aBord et al 1997;Wyart & Palmeri 1998;Palmeri et al 2001;Li et al 2001;Li & Jiang 1999;Wahlgren et al 2001;Fedchak et al 2000;Li et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Radiative lifetime measurements and oscillator strengths of astrophysical interest in Ho III

Zhang¹,

Somesfalean²,

Svanberg³

et al. 2002

A&A

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Abstract. Radiative lifetimes of three long-lived levels belonging to the 4f 10 5d configuration of Ho III have been measured, for the first time, using the time-resolved laser-induced fluorescence technique. A good agreement between the experimental lifetimes and theoretical results obtained within a multiconfigurational pseudo-relativistic Hartree-Fock (HFR) approach including core-polarization (CP) effects is observed provided an adequate scaling factor is applied to the <4f|r|5d> transition matrix element. From the comparison theory-experiment, it has been possible to assess the reliability of the oscillator strengths of the 4f-5d transitions of astrophysical interest, particularly for the lines depopulating the levels considered in the present work. The present results fill in a gap concerning the f -values of doubly ionized holmium and are needed for a quantitative evaluation of the holmium abundance in some peculiar stars.

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Dysprosium III lines in the spectra of peculiar A and B stars

Cited by 24 publications

References 0 publications

Measurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in Nd III

Measurement of lifetimes by laser-induced fluorescence and determination of transition probabilities of astrophysical interest in Nd III

Ab initio calculations of oscillator strengths and Landé factors for NdIII

Radiative lifetime measurements and oscillator strengths of astrophysical interest in Ho III

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