Experimental Radiative Lifetimes, Branching Fractions, and Oscillator Strengths for La<scp>ii</scp>and a New Determination of the Solar Lanthanum Abundance

Lawler, J. E.; Bonvallet, G. A.; Sneden, Christopher

doi:10.1086/321549

Cited by 323 publications

(271 citation statements)

References 31 publications

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“…We adopted the hfs data and isotopic ratios listed in Paper I. The hfs data and isotopic ratios for the Eu II line has been kindly provided by C. Sneden whose linelist uses the gf -values provided by Lawler et al (2001). For the Rb I line, the number of hfs components, the accurately known wavelengths and the relative strength of each component were taken from Lambert & Luck's (1976) analysis of the Rb I resonance line in the Arcturus spectrum and a reliable log gf value of +0.13± 0.04 from Wiese & Martin (1980).…”

Section: Abundances and Error Estimationmentioning

confidence: 99%

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

Reddy

Giridhar

Lambert

2015

Monthly Notices of the Royal Astronomical Society

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We have analyzed high-resolution echelle spectra of red giant members for seven open clusters in the Galactic anticentre direction to explore their chemical compositions. Cluster membership has been confirmed by radial velocity. The spread in temperatures and gravities being very small among the red giants, nearly the same stellar lines were employed for all stars thereby reducing the abundance errors: the errors of the average abundance for a cluster were generally in the 0.02 to 0.05 dex range. Our present sample covers Galactocentric distances of 8.3 to 11.3 kpc and an age range of 0.2 to 4.3 Gyr. A careful comparison of our results for the cluster NGC 2682 (M 67) to other high-resolution abundance studies in the literature shows general good agreement for almost all elements in common.

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Section: Abundances and Error Estimationmentioning

confidence: 99%

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

Reddy

Giridhar

Lambert

2015

Monthly Notices of the Royal Astronomical Society

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“…We compiled a long list of spectral lines from the literature, starting with Biazzo et al (2012). In particular, our line list com- (2000), Lawler et al (2001b), andDen Hartog et al (2003), where the HFS by Gallagher et al (2010) and Lawler et al (2001a) was adopted for Ba and La, respectively. Solar isotopic ratios by Anders & Grevesse (1989) CNO abundances were measured as follows.…”

Section: Differential Elemental Abundancesmentioning

confidence: 99%

The GAPS programme with HARPS-N at TNG

Biazzo

Gratton

Desidera

et al. 2015

A&A

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Binary stars hosting exoplanets are a unique laboratory where chemical tagging can be performed to measure the elemental abundances of both stellar components with high accuracy, with the aim to investigate the formation of planets and their subsequent evolution. Here, we present a high-precision differential abundance analysis of the XO-2 wide stellar binary based on high-resolution HARPS-N at TNG spectra. Both components are very similar K-dwarfs and host planets. Since they formed presumably within the same molecular cloud, we expect that they possess the same initial elemental abundances. We investigated whether planets can cause some chemical imprints in the stellar atmospheric abundances. We measure abundances of 25 elements for both stars with a range of condensation temperature T C = 40−1741 K, achieving typical precisions of ∼0.07 dex. The northern component shows abundances in all elements higher by +0.067 ± 0.032 dex on average, with a mean difference of +0.078 dex for elements with T C > 800 K. The significance of the XO-2N abundance difference relative to XO-2S is at the 2σ level for almost all elements. We discuss that this result might be interpreted as the signature of the ingestion of material by XO-2N or depletion in XO-2S that is due to locking of heavy elements by the planetary companions. We estimate a mass of several tens of M ⊕ in heavy elements. The difference in abundances between XO-2N and XO-2S shows a positive correlation with the condensation temperatures of the elements, with a slope of (4.7 ± 0.9) × 10 −5 dex K −1 , which could mean that both components have not formed terrestrial planets, but first experienced the accretion of rocky core interior to the subsequent giant planets.

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“…Further constants were taken from Holt et al (1999) for Mn II (g f -values from Martinson et al 1977), Rutten (1978) compiled data for Ba, Lawler et al (2001a) give measurements for La, Ivarsson et al (2001) for Pr, and Lawler et al (2001bLawler et al ( , 2004 for Eu and Ho. Molecular line data for four different species (CH, NH, OH and CN) were assembled for the abundance measurements of the CNO elements.…”

Section: Line Datamentioning

confidence: 99%

The Hamburg/ESO R-process enhanced star survey (HERES)

Hayek

Wiesendahl

Christlieb

et al. 2009

A&A

109

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AstrophysicsThe Hamburg/ESO R-process enhanced star survey (HERES) The analysis is based on high-quality VLT/UVES spectra and MARCS model atmospheres. We detect lines of 15 heavy elements in the spectrum of CS 29491−069, and 18 in HE 1219−0312; in both cases including the Th II 4019 Å line. The heavy-element abundance patterns of these two stars are mostly well-matched to scaled solar residual abundances not formed by the s-process. We also compare the observed pattern with recent high-entropy wind (HEW) calculations, which assume core-collapse supernovae of massive stars as the astrophysical environment for the r-process, and find good agreement for most lanthanides. The abundance ratios of the lighter elements strontium, yttrium, and zirconium, which are presumably not formed by the main r-process, are reproduced well by the model. Radioactive dating for CS 29491−069 with the observed thorium and rare-earth element abundance pairs results in an average age of 9.5 Gyr, when based on solar r-process residuals, and 17.6 Gyr, when using HEW model predictions. Chronometry seems to fail in the case of HE 1219−0312, resulting in a negative age due to its high thorium abundance. HE 1219−0312 could therefore exhibit an overabundance of the heaviest elements, which is sometimes called an "actinide boost".IV

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

Cited by 323 publications

References 31 publications

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

The GAPS programme with HARPS-N at TNG

The Hamburg/ESO R-process enhanced star survey (HERES)

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