The Spectrum and Term System of Fe II

Johansson, Sveneric

doi:10.1088/0031-8949/18/4/004

Cited by 172 publications

(101 citation statements)

References 14 publications

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“…There is a remarkable coincidence between several Fe ii lines measured by Johansson (1978) (Table 6, Col. 3) and the unidentified lines in our spectra. However, they are not predicted by the synthetic spectrum either because they are missing in the line lists or owing to their assigned log g f 's which were too low.…”

Section: Unidentified Linessupporting

confidence: 59%

A refined analysis of the remarkable Bp star HR 6000

Castelli

Hubrig

2007

A&A

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Aims. UVES spectra of the very young ( ∼ 10 7 years) peculiar B-type star HR 6000 were analyzed in the near-UV and visual spectral regions (3050-9460 Å) with the aim to extend to other spectral ranges the study made previously in the UV using IUE spectra. Methods. Stellar parameters T eff =12850 K, log g=4.10, and ξ=0 km s −1 , as determined from H β , H γ , H δ Balmer profiles and from the Fe i, Fe ii ionization equilibrium, were used to compute an individual abundances ATLAS12 model. We identified spectral peculiarities and obtained final stellar abundances by comparing observed and computed equivalent widths and line profiles.Results. The adopted model fails to reproduce the (b-y) and c color indices. The spectral analysis has revealed: the presence of emission lines for Mn ii, Cr ii, and Fe ii; isotopic anomalies for Hg , Ca ; the presence of interstellar lines of Na i at λλ 3302.3, 3302.9, 5890, 5896 Å, and of K i at 7665, 7699 Å; the presence of a huge quantity of unidentified lines, which we presume to be mostly due to Fe ii transitions owing to the large Fe overabundance amounting to [+0.7]. The main chemical peculiarities are an extreme overabundance of Xe, followed by those of Hg, P, Y, Mn, Fe, Be, and Ti. The most underabundant element is Si, followed by C, N, Al, S, Mg, V, Sr, Co, Cl, Sc, and Ni. The silicon underabundance [−2.9] is the lowest value for Si ever observed in any HgMn star. The observed lines of He i can not be reproduced by a single value of the He abundance, but they require values ranging from [−0.8] to [−1.6]. Furthermore, when the observed and computed wings of He i lines are fitted, the observed line cores are much weaker than the computed ones. From the present analysis we infer the presence of vertical abundance stratification for He, Mn, and possibly also P.

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Section: Unidentified Linessupporting

confidence: 59%

A refined analysis of the remarkable Bp star HR 6000

Castelli

Hubrig

2007

A&A

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“…The probing scheme used in this study is shown in Fig. 1 with A-values from Baschek et al (1970), Kostyk & Orlova (1982) and Ralchenko et al (2008) and energy levels from Johansson (1978).…”

Section: Experimental Measurementsmentioning

confidence: 99%

The FERRUM project: transition probabilities for forbidden lines in [Fe II] and experimental metastable lifetimes

Gurell

Hartman

Blackwell-Whitehead

et al. 2009

A&A

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Context. Accurate transition probabilities for forbidden lines are important diagnostic parameters for low-density astrophysical plasmas. In this paper we present experimental atomic data for forbidden [Fe ii] transitions that are observed as strong features in astrophysical spectra.Aims. We measure lifetimes for the 3d 6 ( 3 G)4s a 4 G 11/2 and 3d 6 ( 3 D)4s b 4 D 1/2 metastable levels in Fe ii and experimental transition probabilities for the forbidden transitions 3d 7 a 4 F 7/2,9/2 -3d 6 ( 3 G)4s a 4 G 11/2 . Methods. The lifetimes were measured at the ion storage ring facility CRYRING using a laser probing technique. Astrophysical branching fractions were obtained from spectra of Eta Carinae, obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. The lifetimes and branching fractions were combined to yield absolute transition probabilities.

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“…Identification of the spectral lines was done on the basis of a recent catalog of Coluzzi (1993), a compilation of Johansson (1978) for Fe ii lines, and a paper by Quinet et al (1996) for [Fe ii] lines. A comparison of our data obtained with different resolutions in the same spectral intervals shows that they are very similar.…”

Section: Line Identificationsmentioning

confidence: 99%

High resolution spectroscopy of the galactic candidate LBV MWC 314

Мирошниченко

Frémat

Houziaux

et al. 1998

Astron. Astrophys. Suppl. Ser.

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Abstract. The results of high-resolution optical spectroscopy obtained for a recently suggested LBV candidate, MWC 314, are presented. Photospheric lines mostly of N ii and S ii have been found for the first time with a resolution of 0.4 − 0.8Å. They imply a N/O overabundance previously reported for AG and HR Car since no O ii absorptions were detected. Nearly 400 emission lines have been identified in the spectrum between 4190 and 8864Å many of which appear double-peaked. No significant P Cyg-type absorption components have been found for the optically thick Balmer lines. This suggests that the stellar wind of MWC 314 is non-spherical and the circumstellar envelope is viewed not edge-on. The systemic velocity measured using the emission lines of ionized metals turned out to be +55 km s −1 , which corresponds to a distance towards the object of 3.0 ± 0.2 kpc, according to the galactic rotation curve. Our analysis of the characteristics of both photospheric and wind lines resulted in an estimate of the object's T eff of nearly 25000 K, which, however, needs further improvement. The other stellar parameters were found to be as follows: log L bol /L = 6.1±0.3, R * = 60 +30 −10 R . Our study confirms that MWC 314 is one of the most luminous stars in the Milky Way.

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The Spectrum and Term System of Fe II

Abstract: The spectnrrn and term system of

Cited by 172 publications

References 14 publications

A refined analysis of the remarkable Bp star HR 6000

A refined analysis of the remarkable Bp star HR 6000

The FERRUM project: transition probabilities for forbidden lines in [Fe II] and experimental metastable lifetimes

High resolution spectroscopy of the galactic candidate LBV MWC 314

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