Atomic transition probabilities, volume II. sodium through calcium :

Wiese, Wolfgang L.; Smith, Mary W.; Miles, Barry

doi:10.6028/nbs.nsrds.22

Cited by 218 publications

(148 citation statements)

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“…This line consists of three fine structure components and has to be studied using the synthetic spectrum method. We used the log g f data of Wiese et al (1969), which were provided by VALD. The value of the oscillation strength of the main component (-0.310) was modified to -0.340 to fit the solar abundance of log ε(S) = 7.21 (Anders & Grevesse 1989).…”

Section: Sulfurmentioning

confidence: 99%

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Chavero

Reza

Domingos³

et al. 2010

A&A

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The relative distribution of abundances of refractory, intermediate, and volatile elements in stars with planets can be an important tool for investigating the internal migration of a giant planet. This migration can lead to the accretion of planetesimals and the selective enrichment of the star with these elements. We report on a spectroscopic determination of the atmospheric parameters and chemical abundances of the parent stars in transiting planets . Adding data for CoRoT-3 and CoRoT-5 from the literature, we find a flat distribution of the relative abundances as a function of their condensation temperatures. For CoRoT-2, the relatively high lithium abundance and intensity of its Li i resonance line permit us to propose an age of 120 Myr, making this star one of the youngest stars with planets to date. We introduce a new methodology to investigate a relation between the abundances of these stars and the internal migration of their planets. By simulating the internal migration of a planet in a disk formed only by planetesimals, we are able, for the first time, to separate the stellar fractions of refractory, intermediate, and volatile rich planetesimals accreting onto the central star. Intermediate and volatile element fractions enriching the star are similar and much larger than those of pure refractory ones. This result is opposite to what has been considered in the literature for the accreting self-enrichment processes of stars with planets. We also show that these results are highly dependent on the model adopted for the disk distribution regions in terms of refractory, intermediate, and also volatile elements and other parameters considered. We note however, that this self-enrichment mechanism is only efficient during the first 20-30 Myr or later in the lifetime of the disk when the surface convection layers of the central star for the first time attain its minimum size configuration.

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Section: Sulfurmentioning

confidence: 99%

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Chavero

Reza

Domingos³

et al. 2010

A&A

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“…Transition probabilities for the lines of atomic species other than iron were obtained from the NIST Atomic Spectra Database (NIST Standard Reference Database 78; see Weise, Smith, & Miles 1969;Fuhr, Martin, & Weise 1988;Weise, Fuhr, & Deters 1996) when possible. Nearly 80% of the lines selected as suitable from the HIRES spectra have transition probabilities from the NIST database.…”

Section: Transition Probabilitiesmentioning

confidence: 99%

Abundances in Stars from the Red Giant Branch Tip to near the Main-Sequence Turnoff in M5

Ramírez

Cohen

2003

The Astronomical Journal

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We present the iron abundance and abundance ratios for 18 elements with respect to Fe in a sample of stars with a wide range in luminosity, from luminous giants to stars near the turnoff in the globular cluster M5. The analyzed spectra, obtained with the High Resolution Echelle Spectrograph at the Keck Observatory, are of high dispersion (R = /D = 35,000). We find that the neutron capture, the iron peak, and the -element abundance ratios show no trend with T eff and low scatter around the mean between the top of the red giant branch and near the main-sequence turnoff, suggesting that at this metallicity non-LTE effects are not important over the range of stellar parameters spanned by our sample. To within the precision of the measurements (about AE0.1 dex), gravitationally induced heavy-element diffusion does not appear to be present among the stars near the main-sequence turnoff studied here. Our work and other recent studies suggest that heavy-element diffusion is inhibited in the surface layers of metal-poor stars. Differences in the Na abundance from star to star that extend to the main-sequence turnoff are detected in our sample in M5. The anticorrelation between O and Na abundances, observed in other metal-poor globular clusters, is not detected in our sample, but it may be hidden among stars with only upper limits for their O abundances. As we found in M71, there is a hint of star-to-star variation in the Zr abundance. Overall the abundance ratios of M5 appear very similar to those of M71, with the possible exception of the neutron capture element Ba, for which we argue that the apparent difference may be due to difficulties in the analysis. As in M71, the -elements Mg, Ca, Si, and Ti are overabundant relative to Fe. The results of our abundance analysis of 25 stars in M5 provide further evidence of abundance variations among specific light elements at unexpectedly low luminosities, which cannot be explained by our current understanding of stellar evolution.

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“…In these cases, the line is marked in italics and is discarded from the LTE average, as would be done in a classical LTE study. Wiese et al (1996); WSM: Wiese et al (1969). …”

Section: Discussionmentioning

confidence: 99%

Candidate exoplanet host HD 131399A: a nascent Am star

Przybilla

Aschenbrenner

Buder

2017

A&A

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Direct imaging suggests that there is a Jovian exoplanet around the primary A-star in the triple-star system HD 131399. We investigate a high-quality spectrum of the primary component HD 131399A obtained with FEROS on the ESO/MPG 2.2 m telescope, aiming to characterise the star's atmospheric and fundamental parameters, and to determine elemental abundances at high precision and accuracy. The aim is to constrain the chemical composition of the birth cloud of the system and therefore the bulk composition of the putative planet. A hybrid non-local thermal equilibrium (non-LTE) model atmosphere technique is adopted for the quantitative spectral analysis. Comparison with the most recent stellar evolution models yields the fundamental parameters. The atmospheric and fundamental stellar parameters of HD 131399A are constrained to T eff = 9200 ± 100 K, log g = 4.37 ± 0.10, M = 1.95 +0.08 −0.06 M , R = 1.51 +0.13 −0.10 R , and log L/L = 1.17 ± 0.07, locating the star on the zero-age main sequence. Non-LTE effects on the derived metal abundances are often smaller than 0.1 dex, but can reach up to ∼0.8 dex for individual lines. The observed lighter elements up to calcium are overall consistent with present-day cosmic abundances, with a C/O ratio of 0.45 ± 0.07 by number, while the heavier elements show mild overabundances. We conclude that the birth cloud of the system had a standard chemical composition, but we witness the onset of the Am phenomenon in the slowly rotating star. We furthermore show that non-LTE analyses have the potential to solve the remaining discrepancies between observed abundances and predictions by diffusion models for Am stars. Moreover, the present case allows mass loss, not turbulent mixing, to be identified as the main transport process competing with diffusion in very young Am stars.

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Atomic transition probabilities, volume II. sodium through calcium :

Cited by 218 publications

References 0 publications

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Distribution of refractory and volatile elements in CoRoT exoplanet host stars

Abundances in Stars from the Red Giant Branch Tip to near the Main-Sequence Turnoff in M5

Candidate exoplanet host HD 131399A: a nascent Am star

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