Solar abundance of praseodymium

Biémont, Émile; Grevesse, N.; Hauge, Ö.

doi:10.1007/bf00155442

Cited by 8 publications

(8 citation statements)

References 8 publications

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“…However, consistent abundances from all five lines were derived: the mean value (Table 3) is log ǫ(Pr) ⊙ = 0.76 ± 0.02 (sigma = 0.04). Our new photospheric abundance is in good agreement with the meteoritic and the Biémont et al (1979) photospheric abundances that were quoted above.…”

Section: Praseodymiumsupporting

confidence: 90%

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NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r -PROCESS-RICH VERY METAL-POOR STARS

Sneden

Lawler

Cowan

et al. 2009

ApJS

201

189

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We have derived new abundances of the rare-earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally-consistent Ba, rare-earth, and Hf (56 ≤ Z ≤ 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

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Section: Praseodymiumsupporting

confidence: 90%

“…However, most of them are very weak and/or blended. An early study by Biémont et al (1979) has a good discussion of the benefits and disadvantages of many of these lines for photospheric abundance work. They used nine lines to derive log ǫ(Pr) ⊙ = 0.71 ± 0.08, 7 with individual lines contributing to the average with different weights.…”

Section: Praseodymiummentioning

confidence: 99%

NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r -PROCESS-RICH VERY METAL-POOR STARS

Sneden

Lawler

Cowan

et al. 2009

ApJS

201

189

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“…The average ILW and LCH abundances agree within 0.01 dex. For each set of atomic parameters and for both solar model atmospheres, the derived Pr abundance is 0.09 dex -0.23 dex larger than that obtained by Biémont et al (1979) and 0.40 dex -0.54 dex larger compared to that of Ivarsson et al (2003). Different studies give the meteoritic CI Chondrites abundance log (Pr/H) met = -11.20±0.04 (Grevesse et al 1996;Palme & Jones 2005), -11.22±0.03 (Lodders 2003) or -11.25±0.03 (Asplund et al 2005).…”

Section: Solar Abundance Of Praseodymiumcontrasting

confidence: 59%

“…We first apply the non-LTE calculations to the Pr abundance analysis for the solar atmosphere. The earlier determinations were performed by Biémont et al (1979) based on the nine lines of Pr ii in the 3990 -5330 Å spectral region and by Ivarsson et al (2003) based on the three lines of Pr ii. The obtained mean abundances of the praseodymium are surprisingly different, log (Pr/H) ⊙ = −11.29±0.08 and log (Pr/H) ⊙ = −11.60±0.1, respectively.…”

Section: Solar Abundance Of Praseodymiummentioning

confidence: 99%

Non-LTE line formation for Pr ii and Pr iii in A and Ap stars

Mashonkina¹,

Ryabchikova

Ryabtsev

et al. 2008

A&A

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Aims. Non-local thermodynamical equilibrium (non-LTE) line formation for singly-ionized and doubly-ionized praseodymium is considered for a range of effective temperatures between 7250 K and 9500 K. We evaluate the influence of departures from LTE on Pr abundance determinations and determine a distribution of the Pr abundance in the atmosphere of the roAp star HD 24 712 from a non-LTE analysis of the Pr ii and Pr iii lines. Methods. A comprehensive model atom for Pr ii/iii is presented based on the measured and the predicted energy levels, in total, 6708 levels of Pr ii and Pr iii and the ground state of Pr iv. Calculations of the Pr ii energy levels and oscillator strengths for the transitions in Pr ii and Pr iii are described.Results. The dependence of non-LTE effects on the atmospheric parameters is discussed. At T eff ≥ 8000 K, departures from LTE lead to the overionization of Pr ii and, therefore, to systematically depleted total absorption in the line and positive abundance corrections. At the lower temperatures, different lines of Pr ii may be either weakened or amplified depending on the line strength. The non-LTE effects strengthen the Pr iii lines and lead to negative abundance corrections. Non-LTE corrections grow with effective temperature for the Pr ii lines, and, in contrast, they decline for the Pr iii lines. The Pr ii/iii model atom is applied to determine the Pr abundance in the atmosphere of the roAp star HD 24 712 from the lines of two ionization stages. In the chemically uniform atmosphere with [Pr/H] = 3, the departures from LTE may explain only a small part (approximately 0.3 dex) of the difference between the LTE abundances derived from the Pr ii and Pr iii lines ( 2 dex). We find that the lines of both ionization stages are fitted for the vertical distribution of praseodymium, where the Pr enriched layer with [Pr/H] ≥ 4 exists in the outer atmosphere at log τ 5000 < −4. The departures from LTE for Pr ii/iii are strong in the stratified atmosphere and have the opposite sign for the Pr ii and Pr iii lines. The praseodymium stratification analysis of roAp stars has to be performed based on non-LTE line formation. Using the revised partition function of Pr ii and experimental transition probabilities, we determine the solar non-LTE abundance to be log (Pr/H) = −11.15 ± 0.08.

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“…Its abundance has been studied through weak lines of Pr II by several authors (see [22] for a tabulated review). The current canonical value, log N Pr 0:71AE0.08 [23] on a scale where log N H 12:0, had been determined from synthetic spectrum ¢tting of nine Pr II lines which were identi¢ed in a high spectral resolution solar atlas. The oscillator strengths in that study were taken from several sources, represented in part by lifetimes determined from beam-foil techniques [24] and [5] as well as correction factors applied to the work of [25].…”

Section: The Solar Abundance Of Prmentioning

confidence: 99%

Accurate Wavelengths, Oscillator Strengths and Hyperfine Structure in Selected Praseodymium Lines of Astrophysical Interest

2001

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The first measurement of a one-dimensional relaxation law is reported. The photocurrent decay of the polydiacetylene PDA-1OH has been measured in the time range (1-2 x lo4) s. The measurements can be extremely well described by an exp(-btlb) law, characteristic of deep trapping in a one-dimensional system. Comparing experiment and theory we are able to estimate trap concentrations and effective jump rates.

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Solar abundance of praseodymium

Abstract: 16 lines of Pr II possibly present in the solar photospheric spectrum have been studied. When including hyperfine structure in synthetic calculations, investigations of 9 lines result in an abundance Avr = 0.71 • in the log AH = 12.00 scale.

Cited by 8 publications

References 8 publications

NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r -PROCESS-RICH VERY METAL-POOR STARS

NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r -PROCESS-RICH VERY METAL-POOR STARS

Non-LTE line formation for Pr ii and Pr iii in A and Ap stars

Accurate Wavelengths, Oscillator Strengths and Hyperfine Structure in Selected Praseodymium Lines of Astrophysical Interest

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