References of "Grevesse, Nicolas"
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See detailExperimental and theoretical radiative decay rates for highly excited ruthenium atomic levels and the solar abundance of ruthenium
Fivet, V.; Quinet, Pascal ULg; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2009), 396

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new ... [more ▼]

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new abundance value (in the usual logarithmic scale where the solar hydrogen abundance is equal to 12.00), ARu = 1.72 ± 0.10, is in agreement with the most recent meteoritic result, ARu = 1.76 ± 0.03. The accuracy of the transition probabilities, obtained using a relativistic Hartree–Fock model including core-polarization effects, has been assessed by comparing the theoretical lifetimes with previous experimental results. A comparison is also made with new measurements performed in this work by the time-resolved laser-induced fluorescence spectroscopy for 10 highly excited odd-parity levels of Ru I [less ▲]

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See detailThe new solar abundances - Part II: the crisis and possible solutions
Montalban Iglesias, Josefa ULg; Miglio, Andrea ULg; Theado, S. et al

in Communications in Asteroseismology (2006), 147

Recent 3D, NLTE analysis of the solar spectrum (Asplund et al. 2006, Part I; Asplund et al. 2005) have led to a significant reduction of the CNO and Ne abundances leading to a (Z/X) 30% smaller than the ... [more ▼]

Recent 3D, NLTE analysis of the solar spectrum (Asplund et al. 2006, Part I; Asplund et al. 2005) have led to a significant reduction of the CNO and Ne abundances leading to a (Z/X) 30% smaller than the previously recommended value. The corresponding decrease in opacity increases dramatically the discrepancies between the sound-speed derived from helioseismology and our new standard solar models (SSM). We present in this paper some numerical experiments trying to reduce this discrepancy. [less ▲]

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See detailSolar Model with CNO Revised Abundances
Montalban Iglesias, Josefa ULg; Miglio, Andrea ULg; Noels-Grötsch, Arlette ULg et al

in Danesy, D. (Ed.) Proceedings of the SOHO 14 / GONG 2004 Workshop (ESA SP-559). "Helio- and Asteroseismology: Towards a Golden Future" (2004, October 01)

Recent three-dimensional, NLTE analyses of the solar spectrum have shown a significant reduction in the C, N, O and Ne abundances leading to a Z/X ratio of the order of 0.0177. We have computed solar ... [more ▼]

Recent three-dimensional, NLTE analyses of the solar spectrum have shown a significant reduction in the C, N, O and Ne abundances leading to a Z/X ratio of the order of 0.0177. We have computed solar models with this new mixture in the OPAL opacity tables. The present He abundance we find seems rather consistent with the helioseismic value. However, the convective envelope is too shallow, and diffusion, even if it reduces the discrepancy, is not able to give the current value. We present some numerical experiments consisting in changing the diffusion velocities and/or the value of opacity at the base of the convective envelope. [less ▲]

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See detailStandard Abundances
Grevesse, Nicolas ULg; Noels-Grötsch, Arlette ULg; Sauval, A. J. et al

in Holt, Stephen S.; Sonneborn, George (Eds.) Proceedings of the sixth (6th) annual October Astrophysics Conference in College Park; Maryland; 9-11 October 1995 (1996)

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See detailA new analysis of the OH radical spectrum from solar Infrared observations.
Mélen, F.; Grevesse, Nicolas ULg; Delbouille, L. et al

in ASP Conference Series (1995)

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See detailA new analysis of the OH radical spectrum from solar infrared observations.
Mélen, F.; Sauval, A. J.; Grevesse, Nicolas ULg et al

in Journal of Molecular Spectroscopy (1995), 174

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See detailThe solar spectrum between 16 and 35 µm.
Sauval; Blomme, R.; Grevesse, Nicolas ULg et al

in Sauval, A. J.; Blomme, R.; Grevesse, Nicolas (Eds.) ASP Conferences (1994)

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See detailAtomic data and the spectrum of the solar photosphere.
Grevesse, Nicolas ULg; Noels-Grötsch, Arlette ULg

in Physica Scripta (1993), 47

Even though the solar photospheric abundances are now on the whole in very good agreement with the meteoritic values, some problems remain which will only be solved with a higher level of accuracy in the ... [more ▼]

Even though the solar photospheric abundances are now on the whole in very good agreement with the meteoritic values, some problems remain which will only be solved with a higher level of accuracy in the atomic data, especially the transition probabilities for faint lines. The authors justify this request for many more very accurate gf-values through a few particularly striking points. [less ▲]

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See detailTi-ii transition probabilities and radiative lifetimes in TI and the solar titanium abundance
Bizzarri, A.; Huber, M. C. E.; Noels-Grötsch, Arlette ULg et al

in Astronomy and Astrophysics (1993), 273

Transition probabilities of 100 Ti-II emission lines, originating from 7 different atomic levels, have been determined by combining branching fractions with radiative lifetimes. The branching fractions ... [more ▼]

Transition probabilities of 100 Ti-II emission lines, originating from 7 different atomic levels, have been determined by combining branching fractions with radiative lifetimes. The branching fractions were measured using Fourier transform spectroscopy on a hollow cathode. The radiative lifetimes of these 7 - and 35 additional - levels were measured using time resolved laser-induced fluorescence on a slow Ti ion beam. The transition probabilities of 21 very weak lines have been used to derive a solar titanium abundance of α[SUB]Ti[/SUB] = log(N[SUB]Ti[/SUB]/N[SUB]H[/SUB]) + 12=5.04±0.04 dex, which is insensitive to the solar model. This value is in disagreement with the meteoritic titanium abundance (4.93±0.02). [less ▲]

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See detailLifetimes in Fe II and the solar abundance of iron
Hannaford, P.; Lowe, R. M.; Grevesse, Nicolas ULg et al

in Astronomy and Astrophysics (1992), 259

New atomic lifetimes have been determined for eight quartet (z 4D, z 4F) levels and ten sextet (z 6D, z 6F, z 6P) levels in Fe II and the results for seven of these levels have been combined with existing ... [more ▼]

New atomic lifetimes have been determined for eight quartet (z 4D, z 4F) levels and ten sextet (z 6D, z 6F, z 6P) levels in Fe II and the results for seven of these levels have been combined with existing experimental branching fractions to obtain a revised set of log gf-values for 15 solar lines in Fe II. The new log gf data are used together with equivalent widths determined from the Liege solar atlas to derive a value for the iron photospheric abundance: 7.48 +/- 0.04, which is consistent with the currently accepted meteoritic result, 7.51 +/- 0.01. The results are compared with the atomic lifetime data, log gf data and solar analyses used in three other recent solar abundance determinations based on Fe II lines. [less ▲]

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See detailCalibration of the Alpha Centauri system - Metallicity and age
Noels-Grötsch, Arlette ULg; Grevesse, Nicolas ULg; Magain, Pierre ULg et al

in Astronomy and Astrophysics (1991), 247

The binary system Alpha Cen A and B, with its well known parallax, its high quality orbit and the reasonable hypothesis of a common origin and age for both components, is a useful test of stellar ... [more ▼]

The binary system Alpha Cen A and B, with its well known parallax, its high quality orbit and the reasonable hypothesis of a common origin and age for both components, is a useful test of stellar evolution models. Evolutionary sequences are computed for 1.085 and 0.9 solar masses with different values of Z, Y and alpha (= l/Hp). Adopting luminosities and effective temperatures as derived from the observations, Z = 0.04, Y = 0.32, alpha = 1.6 and t = 5 Gyr. The Z-value derived from evolutionary sequences is very sensitive to the difference in effective temperature between the two components. [less ▲]

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