IMPROVED Ni I log(
                    <i>gf</i>
                    ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

Wood, Michael P.; Lawler, J. E.; Sneden, C.; Cowan, J. J.

doi:10.1088/0067-0049/211/2/20

Cited by 90 publications

(46 citation statements)

References 58 publications

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“…The longterm objective of our studies is to map the relative abundances of Fe-group elements at low metallicity. This paper complements the very recent studies on V I ) and V II (Wood et al 2014a) and recent work on other spectra including Cr I (Sobeck et al 2007), Mn I and Mn II , Ti I , Ti II , Ni I (Wood et al 2014b), and Fe I Ruffoni et al 2014). Our new transition probability data are supplemented with improved isotopic and hyperfine structure (hfs) data as needed.…”

Section: Introductionmentioning

confidence: 61%

IMPROVED Co i log( gf ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

Lawler

Sneden

Cowan

2015

ApJS

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New emission branching fraction measurements for 898 lines of the first spectrum of cobalt (Co I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer on Kitt Peak, AZ and a high-resolution echelle spectrometer. Published radiative lifetimes from laser induced fluorescence measurements are combined with the branching fractions to determine accurate absolute atomic transition probabilities for the 898 lines. Hyperfine structure (hfs) constants for levels of neutral Co in the literature are surveyed and selected values are used to generate complete hfs component patterns for 195 transitions of Co I. These new laboratory data are applied to determine the Co abundance in the Sun and metal-poor star HD 84937, yielding log ε(Co) = 4.955 ± 0.007 (σ = 0.059) based on 82 Co I lines and log ε(Co) = 2.785 ± 0.008 (σ = 0.065) based on 66 Co I lines, respectively. A Saha or ionization balance test on the photosphere of HD 84937 is performed using 16 UV lines of Co II, and good agreement is found with the Co I result in this metal-poor ([Fe I/H] = −2.32, [Fe II/H] = −2.32) dwarf star. The resulting value of [Co/Fe] = +0.14 supports a rise of Co/ Fe at low metallicity that has been suggested in other studies.

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Section: Introductionmentioning

confidence: 61%

IMPROVED Co i log( gf ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

Lawler

Sneden

Cowan

2015

ApJS

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“…Brault & Holweger 1981; Wickliffe & Lawler (1997), which the authors placed on an absolute scale using the TRLIF lifetimes of Bergeson & Lawler (1993b). These have recently been updated and greatly extended by Wood et al (2014b). A small number of highquality g f -values are also available from Johansson et al (2003), based upon FTS BFs and a single TRLIF lifetime.…”

Section: Nickelmentioning

confidence: 99%

“…Wherever available, we employ isotopic separations from Wood et al (2014b), who fitted the isotopic shifts of a large number of Ni  energy levels to earlier spectroscopic data. Much of the power of that analysis can be attributed to the accurate FTS wavelengths of 58 Ni and 60 Ni line components recorded by Litzen et al (1993) Table 2.…”

Section: Isotopic Structurementioning

confidence: 99%

“…Here we update those results using an improved 3D solar model atmosphere (AGSS09; Paper I). Wood et al (2014b) found log Ni = 6.28 ± 0.06 by employing spectrum synthesis of Ni  lines, the HM model and new laboratory oscillator strengths. The previous reference solar Ni abundance (Grevesse & Sauval 1998;Asplund et al 2005a;Grevesse et al 2007) was log Ni = 6.25 ± 0.09, from an HM-based analysis of Ni  by Biémont et al (1980).…”

Section: Introductionmentioning

confidence: 99%

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The elemental composition of the Sun

Scott

Asplund

Grevesse

et al. 2014

A&A

264

202

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We redetermine the abundances of all iron group nuclei in the Sun, based on neutral and singly-ionised lines of Sc, Ti, V, Mn, Fe, Co and Ni in the solar spectrum. We employ a realistic 3D hydrodynamic model solar atmosphere, corrections for departures from local thermodynamic equilibrium (NLTE), stringent line selection procedures and high quality observational data. We have scoured the literature for the best quality oscillator strengths, hyperfine constants and isotopic separations available for our chosen lines. We find log Sc = 3.16 ± 0.04, log Ti = 4.93 ± 0.04, log V = 3.89 ± 0.08, log Cr = 5.62 ± 0.04, log Mn = 5.42 ± 0.04, log Fe = 7.47 ± 0.04, log Co = 4.93 ± 0.05 and log Ni = 6.20 ± 0.04. Our uncertainties factor in both statistical and systematic errors (the latter estimated for possible errors in the model atmospheres and NLTE line formation). The new abundances are generally in good agreement with the CI meteoritic abundances but with some notable exceptions. This analysis constitutes both a full exposition and a slight update of the preliminary results we presented in Asplund et al. (2009, ARA&A, 47, 481), including full line lists and details of all input data we employed.

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“…In addition, highly excited lines such as the ones reported in this paper, can be used as probes of deviations from local thermodynamic equilibrium (LTE) in stellar atmospheres. With known f -values, the highly excited lines benchmark the stellar atmospheres and aid in the determination of excitation distributions (Wood et al 2014). A search was made for the lines in HD 84937, the solar type star α Cen A and the sun (Hinkle et al 2005;Moore et al 1982), but the temperature and the Boltzmann factor were too small to determine an abundance using these lines.…”

Section: Introductionmentioning

confidence: 99%

The FERRUM project: Experimental transition probabilities from highly excited even 5s levels in Cr ii

Engström

Lundberg

Nilsson

et al. 2014

A&A

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We report lifetime measurements of the five levels in the 3d 4 (a 5 D)5s e 6 D term in Cr  at an energy around 83 000 cm −1 , and log(g f ) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the plasma, we used a two-photon excitation scheme. This process is greatly facilitated by the presence of the 3d 4 (a 5 D)4p z 6 F levels at roughly half the energy difference. The f -values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode lamp recorded with a Fourier transform spectrometer.

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IMPROVED Ni I log( gf ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

Cited by 90 publications

References 58 publications

IMPROVED Co i log( gf ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

IMPROVED Co i log( gf ) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

The elemental composition of the Sun

The FERRUM project: Experimental transition probabilities from highly excited even 5s levels in Cr ii

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