Effective Collision Strengths for Electron Impact Excitation of Singly Ionized Sulfur

Ramsbottom, Catherine; Bell, K L; Stafford, R. P.

doi:10.1006/adnd.1996.0009

Cited by 75 publications

(40 citation statements)

References 6 publications

(10 reference statements)

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“…We note that new R-matrix calculations have recently been carried out for S II by Ramsbottom et al (1996), including 43 fine-structure levels, up to the n = 4 configurations. These will be assessed in the next release of CHIANTI.…”

Section: S IImentioning

confidence: 99%

CHIANTI - an atomic database for emission lines

Dere

Landi

Mason

et al. 1997

Astron. Astrophys. Suppl. Ser.

1,916

1,669

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Abstract. A comprehensive set of accurate atomic data is required for analyses of astrophysical and solar spectra. CHIANTI provides a database of atomic energy levels, wavelengths, radiative data and electron excitation data for ions which are abundant in cosmic plasmas. The most recent electron excitation data have been assessed and stored following the method of Burgess & Tully (1992). The current version is essentially complete for specifying the emission spectrum at wavelengths greater than 50Å. A list of observed lines in the spectral region between 50 and 1100Å has been compiled and compared with the lines predicted by the CHIANTI database. The CHIANTI database reproduces the vast majority of lines observed at these wavelengths. CHIANTI includes IDL (Interactive Data Language) routines to calculate optically thin synthetic spectra for equilibrium conditions. IDL routines to calculate theoretical line intensities required for electron density or temperature diagnostics and emission measure studies are also included. The CHIANTI atomic database and supporting IDL routines are available by anonymous FTP.

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Section: S IImentioning

confidence: 99%

CHIANTI - an atomic database for emission lines

Dere

Landi

Mason

et al. 1997

Astron. Astrophys. Suppl. Ser.

1,916

1,669

View full text Add to dashboard Cite

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“…5.1), we consider 10 Taking into account the lack of O 2+ in the nebula and the similarity between ionization potentials of O + (35.12 eV) and S 2+ (34.83 eV), this seems to be a reasonable conclusion. 11 The atomic dataset used by these authors was the following: collision strengths by Ramsbottom et al (1996) for S + and Tayal & Gupta (1999) for S 2+ . Transition probabilities by Keenan et al (1993) for S + and Mendoza & Zeippen (1982) and Kaufman & Sugar (1986) for S 2+ .…”

Section: Sulphurmentioning

confidence: 99%

The Cocoon nebula and its ionizing star: do stellar and nebular abundances agree?

García‐Rojas

Esteban

2014

A&A

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Context. Main-sequence massive stars embedded in an H ii region should have the same chemical abundances as the surrounding nebular gas+dust. The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474), is an ideal target to compare nebular and stellar abundances in detail in the same Galactic region. Aims. We investigate the chemical content of oxygen and other elements in the Cocoon nebula from two different points of view: an empirical analysis of the nebular spectrum, and a detailed spectroscopic analysis of the associated early B-type star using state-ofthe-art stellar atmosphere modeling. By comparing the stellar and nebular abundances, we aim to indirectly address the long-standing problem of the discrepancy found between abundances obtained from collisionally excited lines and optical recombination lines in photoionized nebulae. Methods. We collected long-slit spatially resolved spectroscopy of the Cocoon nebula and a high-resolution optical spectrum of the ionizing star. Standard nebular techniques along with updated atomic data were used to compute the physical conditions and gaseous abundances of O, N, and S in eight apertures extracted across a semidiameter of the nebula. We performed a self-consistent spectroscopic abundance analysis of BD+46 3474 based on the atmosphere code FASTWIND to determine the stellar parameters and Si, O, and N abundances. Results. The Cocoon nebula and its ionizing star, located at a distance of 800 ± 80 pc, have a chemical composition very similar to the Orion nebula and other B-type stars in the solar vicinity. This result agrees with the high degree of homogeneity of the presentday composition of the solar neighborhood (up to 1.5 Kpc from the Sun) as derived from the study of the local cold-gas interstellar medium. The comparison of stellar and nebular collisionally excited line abundances in the Cocoon nebula indicates that O and N gas+dust nebular values agree better with stellar values assuming small temperature fluctuations on the order of those found in the Orion nebula (t 2 = 0.022). For S, the behaviour is somewhat puzzling, and different conclusions can be reached depending on the atomic data set used.

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“…Since a picture tells more than one thousand words, there is no better answer to such question than a plot describing a real science case. (Podobedova et al (2009);Ramsbottom et al (1996);Tayal & Zatsarinny (2010)). It can easily be seen that the results depend strongly on the data used: for example, the peak density changes by up to a factor of 3 (from ≈ 5000 cm −3 to ≈ 15000 cm −3 ), while the peak temperature changes by ≈ 5000 K.…”

Section: Do Uncertainties Matter?mentioning

confidence: 99%

Report on the Tenerife Workshop on Uncertainties in Atomic Data and How They Propagate in Chemical Abundances

Luridiana¹,

García‐Rojas²

2011

Proc. IAU

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Abstract. In 2010, we organised a workshop in Tenerife with the aim of bringing together scientists concerned with the completeness and accuracy of atomic data for astrophysical applications. Participants included atomic physicists, theoretical astrophysicists and astronomers, and the workshop covered topics such as the evaluation of uncertainties in atomic data, the propagation of such uncertainties in chemical abundances, and the feedback between observations and calculations. Communication issues were also discussed, including questions such as: How can it be ensured that atomic data are correctly understood and used? Which forum is the best one for a fluid interaction between all communities involved in the production and use of atomic data? This contribution lays out the main issues raised during the workshop and some of the solutions proposed.

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Effective Collision Strengths for Electron Impact Excitation of Singly Ionized Sulfur

Cited by 75 publications

References 6 publications

CHIANTI - an atomic database for emission lines

CHIANTI - an atomic database for emission lines

The Cocoon nebula and its ionizing star: do stellar and nebular abundances agree?

Report on the Tenerife Workshop on Uncertainties in Atomic Data and How They Propagate in Chemical Abundances

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