High resolution spectroscopy of iridium in a hollow cathode discharge

Gianfrani, L.; Tino, G. M.

doi:10.1007/bf01450162

Cited by 4 publications

(2 citation statements)

References 12 publications

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“…Both are accessible to the r-process and have nuclear spin I = 3/2. The HFS and IS have been measured by Büttgenbach et al (1978), Bürger et al (1984), and Gianfrani & Tino (1993) for one of the Ir I lines that is useful for abundance work, λ2924.790. This line connects an upper 5d 7 6s( 5 F)6p configuration to the ground 5d 7 6s 2 configuration.…”

Section: A35 Tungsten (W Z = 74)mentioning

confidence: 99%

The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925*

Roederer

Lawler

Hartog

et al. 2022

ApJS

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We present a nearly complete rapid neutron-capture process (r-process) chemical inventory of the metal-poor ([Fe/H] = −1.46 ± 0.10) r-process-enhanced ([Eu/Fe] = +1.32 ± 0.08) halo star HD 222925. This abundance set is the most complete for any object beyond the solar system, with a total of 63 metals detected and seven with upper limits. It comprises 42 elements from 31 ≤ Z ≤ 90, including elements rarely detected in r-process-enhanced stars, such as Ga, Ge, As, Se, Cd, In, Sn, Sb, Te, W, Re, Os, Ir, Pt, and Au. We derive these abundances from an analysis of 404 absorption lines in ultraviolet spectra collected using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope and previously analyzed optical spectra. A series of appendices discusses the atomic data and quality of fits for these lines. The r-process elements from Ba to Pb, including all elements at the third r-process peak, exhibit remarkable agreement with the solar r-process residuals, with a standard deviation of the differences of only 0.08 dex (17%). In contrast, deviations among the lighter elements from Ga to Te span nearly 1.4 dex, and they show distinct trends from Ga to Se, Nb through Cd, and In through Te. The r-process contribution to Ga, Ge, and As is small, and Se is the lightest element whose production is dominated by the r-process. The lanthanide fraction, log X La = −1.39 ± 0.09, is typical for r-process-enhanced stars and higher than that of the kilonova from the GW170817 neutron-star merger event. We advocate adopting this pattern as an alternative to the solar r-process-element residuals when confronting future theoretical models of heavy-element nucleosynthesis with observations.

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Section: A35 Tungsten (W Z = 74)mentioning

confidence: 99%

The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925*

Roederer

Lawler

Hartog

et al. 2022

ApJS

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“…We took hyperfine A and B constants for the ground level from Büttgenbach et al's (1978) extremely accurate atomic-beam magnetic-resonance measurements. Upper level hyperfine constants were taken from Gianfrani & Tito (1993) for the 3220 Å line and from Murakawa and Suwa (1952) for the 3513 Å and 3800 Å lines. The log gf = -0.52 for the 3220 Å line was taken from Gough et al (1983).…”

Section: A Substructure Of Neutral Iridium Transitionsmentioning

confidence: 99%

Hubble Space TelescopeObservations of Heavy Elements in Metal‐Poor Galactic Halo Stars

Cowan

Sneden

Beers

et al. 2005

ApJ

121

160

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We present new abundance determinations of neutron-capture elements Ge, Zr, Os, Ir, and Pt in a sample of 11 metal-poor (-3.1 ≤ [Fe/H] ≤ -1.6) Galactic halo giant stars, based on Hubble Space Telescope UV and Keck I optical high-resolution spectroscopy. The stellar sample is dominated by r-process-rich stars such as the well-studied CS 22892-052 and BD +17 • 3248, but also includes the r-process-poor, bright giant HD 122563. Our results demonstrate that abundances of the 3 rd r-process peak elements Os, Ir and Pt in these metal-poor halo stars are very well-correlated among themselves, and with the abundances of the canonical r-process element Eu (determined in other studies), thus arguing for a common origin or site for r-process nucleosynthesis of heavier (Z > 56) elements. However, the large (and correlated) scatters of [Eu,Os,Ir,Pt/Fe] suggests that the heaviest neutron-capture r-process elements are not formed in all supernovae. In -2contrast, the Ge abundances of all program stars track their Fe abundances, very well. An explosive process on iron-peak nuclei (e.g., the α-rich freeze-out in supernovae), rather than neutron capture, appears to have been the dominant synthesis mechanism for this element at low metallicities -Ge abundances seem completely uncorrelated with Eu. The correlation (with very small scatter) of Ge and Fe abundances suggests that Ge must have been produced rather commonly in stars -even at early times in the Galaxy -over a wide range of metallicity. The Zr abundances show much the same behavior as Ge with (perhaps) somewhat more scatter, suggesting some variations in abundance with respect to Fe. The Zr abundances also do not vary cleanly with Eu abundances, indicating a synthesis origin different than that of heavier neutron-capture elements.Detailed abundance distributions, for CS 22892-052 and BD +17 • 3248, combining the new elemental determinations for Os-Pt and recently published Nd and Ho measurements, show excellent agreement with the solar system r-process curve from the elements Ba to Pb. The lighter n-capture elements, including Ge, in general fall below the same solar system r-process curve that matches the heavier elements. Platinum: Den Hartog et al. (2005) have recently completed a new laboratory transi-

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77-Ir Iridium

Fricke

Heilig

Nuclear Charge Radii

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High resolution spectroscopy of iridium in a hollow cathode discharge

Cited by 4 publications

References 12 publications

The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925*

The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925*

Hubble Space TelescopeObservations of Heavy Elements in Metal‐Poor Galactic Halo Stars

77-Ir Iridium

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