Calculations of wavelengths and transition probabilities in the singlet and triplet spectra of N IV

Laughlin, C.

doi:10.1088/0031-8949/42/5/008

Cited by 4 publications

(1 citation statement)

References 22 publications

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“…Our original models failed to reproduce this line, which was traced to a problem with the theoretical model atom. In the atomic data calculations the levels designations of the 2s 4s 3 S o with the 2p 3p 3 P o level (as previously noted by Laughlin 1990;Allard et al 1991) are inverted relative to the spectroscopic designations. When we rectified this inversion, emission in N iv λ6212-6220 was correctly reproduced.…”

Section: Formation Of Some Specific Linesmentioning

confidence: 99%

Properties of Galactic early-type O-supergiants

Bouret

Hillier

Lanz

et al. 2012

A&A

167

308

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Aims. We aim to constrain the properties and evolutionary status of early and mid-spectral type supergiants (from O4 to O7.5). These posses the highest mass-loss rates among the O stars, and exhibit conspicuous wind profiles.Methods. Using the non-LTE wind code cmfgen we simultaneously analyzed the FUV-UV and optical spectral range to determine the photospheric properties and wind parameters. We derived effective temperatures, luminosities, surface gravities, surface abundances, mass-loss rates, wind terminal velocities, and clumping filling factors. Results. The supergiants define a very clear evolutionary sequence, in terms of ages and masses, from younger and more massive stars to older stars with lower initial masses. O4 supergiants cluster around the 3 Myr isochrone and are more massive than 60 M , while the O5 to O7.5 stars have masses in the range 50−40 M and are 4 ± 0.3 Myr old. The surface chemical composition is typical of evolved O supergiants (nitrogen-rich, carbon-and oxygen-poor). While the observed ranges of carbon and nitrogen mass-fractions are compatible with those expected from evolutionary models for the measured stellar masses, the N/C ratios as a function of age are inconsistent with the theoretical predictions for the four earliest (O4 spectral type) stars of the sample. We question the efficiency of rotational mixing as a function of age for these stars and suggest that another mechanism may be needed to explain the observed abundance patterns. Mass-loss rates derived with clumped-models range within a factor of three of the theoretical mass-loss rates. The corresponding volume-filling factors associated with small-scale clumping are 0.05 ± 0.02. Clumping is found to start close to the photosphere for all but three stars, two of which are fast rotators.

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Section: Formation Of Some Specific Linesmentioning

confidence: 99%

Properties of Galactic early-type O-supergiants

Bouret

Hillier

Lanz

et al. 2012

A&A

167

308

View full text Add to dashboard Cite

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Multi-configuration Dirac-Fock and relativistic quantum defect orbital study of triplet-triplet transitions in beryllium-like ions

Charro

Martı́n

Lavín

1996

Journal of Quantitative Spectroscopy and Radiative Transfer

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Commission 14: Atomic and Molecular Data (Donnees Atomiques Et Moleculaires)

Martin¹,

Wiese²,

Gallagher³

et al. 1994

Trans. Int. Astron. Union

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In recent years the interaction between astrophysics and atomic physics has entered a new stage. On one hand, increasingly powerful, high resolution astronomical spectrometers and other observational instruments, especially those for recent space and astronomy missions, have created vastly increased demands for more detailed and more accurate data on atomic and molecular processes. On the other hand, the advent of large-scale computing capabilities has been an important development for the atomic physics community, giving it opportunities to embark on comprehensive data generation projects that were unthinkable until recently. Indeed, several huge data projects have now come to successful conclusion. These projects have not only generated vast amounts of new data, but have also in many cases far surpassed the earlier data in their accuracy.

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Calculations of wavelengths and transition probabilities in the singlet and triplet spectra of N IV

Cited by 4 publications

References 22 publications

Properties of Galactic early-type O-supergiants

Properties of Galactic early-type O-supergiants

Multi-configuration Dirac-Fock and relativistic quantum defect orbital study of triplet-triplet transitions in beryllium-like ions

Commission 14: Atomic and Molecular Data (Donnees Atomiques Et Moleculaires)

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