gf-values for singly ionized lanthanum based on a new calibration of NBS Monograph 145 intensities

Bord, D. J.; Barisciano, L. P.; Cowley, Charles R.

doi:10.1093/mnras/278.4.997

Cited by 26 publications

(32 citation statements)

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“…We also derived abundances by using line synthesis for nine elements The code used for the abundance analysis was developed by Monique Spite (1967) and has been improved over the years. We note that both model atmospheres and the line synthesis program are in spherical geometry, so errors due to geometry (Lawler et al 2001, with log g f from Bord et al 1996), Cu (Biehl 1976), and Co I and Sc II (Prochaska et al 2000). In Fig.…”

Section: Abundance Determinationmentioning

confidence: 98%

Chemical abundances in LMC stellar populations

Pompéia

Hill

Spite

et al. 2008

A&A

146

194

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Aims. We have used FLAMES (the Fibre Large Array Multi Element Spectrograph) at the VLT-UT2 telescope to obtain spectra of a large sample of red giant stars from the inner disk of the LMC, ∼2 kpc from the center of the galaxy. We investigate the chemical abundances of key elements to understand the star formation and evolution of the LMC disk: heavy and light [s-process/Fe] and [α/Fe] give constraints on the time scales of formation of the stellar population. Cu, Na, Sc, and the iron-peak elements are also studied aiming to better understand the build up of the elements of this population and the origin of these elements. We aim to provide a more complete picture of the LMC's evolution by compiling a large sample of field star abundances. Methods. LTE abundances were derived using line spectrum synthesis or equivalent width analysis. We used OSMARCS model atmospheres and an updated line list. The [heavy-s/light-s] ratios are high, showing a slow, increasing trend with metallicity. We were surprised to find an offset for three of the iron-peak elements. We found an offset for the [iron-peak/Fe] ratios of Ni, Cr, and Co, with an underabundant pattern and subsolar values, while Vanadium ratios track the solar value. Copper shows very low abundances in our sample for all metallicities, compatible with those of the Galaxy only for the most metal-poor stars. The overall chemical distributions of this LMC sample indicates a slower star formation history relative to that of the solar neighborhood, with a higher contribution from type Ia supernovae relative to type II supernovae.

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Section: Abundance Determinationmentioning

confidence: 98%

Chemical abundances in LMC stellar populations

Pompéia

Hill

Spite

et al. 2008

A&A

146

194

View full text Add to dashboard Cite

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“…recommended by Bord et al (1996) to log 10 gf our values for lines of La II as a function of our log 10 gf. Thevenin (1989Thevenin ( , 1990) from the solar spectrum.…”

Section: Fig 3ècomparison Ofmentioning

confidence: 99%

“…Figures 1È3 show comparisons of our to values log 10 gf from Bord, Barisciano, & Cowley (1996) as function of wavelength, upper level energy, and line strength. The transition probabilities from Bord et al are actually based on a their recalibration of the NBS Monograph 145 intensities (Meggers, Corliss, & Scribner 1975 Figure 1 shows no systematic wavelength-dependent error and that Figure 2 shows almost no systematic error dependent on the energy of the upper level.…”

Section: Branching Fraction Measurementsmentioning

confidence: 99%

Experimental Radiative Lifetimes, Branching Fractions, and Oscillator Strengths for Laiiand a New Determination of the Solar Lanthanum Abundance

Lawler

Bonvallet

Sneden

2001

ApJ

319

263

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Radiative lifetimes, accurate in most cases to^5%, from time-resolved laser-induced Ñuorescence measurements on a slow beam of lanthanum ions are reported for 31 odd-parity levels of La II. Experimental branching fractions for La II from emission spectra covering the near-ultraviolet to the nearinfrared are also reported. The spectra were recorded using the US National Solar Observatory 1.0 m Fourier transform spectrometer. The branching fractions are combined with the radiative lifetimes to produce 84 experimentally determined transition probabilities or oscillator strengths, generally accurate to^10%, for La II. These new experimental results are compared to older experimental and theoretical results. These data are applied to determine a new value for the solar photospheric lanthanum abundance, with estimated internal errors of^0.03 and external errors of^0.03. Slog 10 v(La)T \ 1.13,

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“…In an attempt to meet this need, our group has carried out ab initio calculations of oscillator strengths for La ii (Bord et al 1996), Ce iii (Bord et al 1997), Nd iii , and Lu ii ) using the Cowan code (Cowan 1981(Cowan , 1985, and we have applied these results in abundance analyses of several CP stars and the Sun. In this paper, a more expansive list of gf -values for predicted features of Nd iii than was given in our earlier work on γ Equulei and HR 6870 is presented.…”

Section: Introductionmentioning

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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gf-values for singly ionized lanthanum based on a new calibration of NBS Monograph 145 intensities

Cited by 26 publications

References 0 publications

Chemical abundances in LMC stellar populations

Chemical abundances in LMC stellar populations

Experimental Radiative Lifetimes, Branching Fractions, and Oscillator Strengths for Laiiand a New Determination of the Solar Lanthanum Abundance

Ab initio calculations of oscillator strengths and Landé factors for NdIII

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