On the identification of molecules in the cool carbon stars

Lambert, David L.

doi:10.1086/132293

Cited by 11 publications

(4 citation statements)

References 25 publications

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“…However, S stars and M giants do have pronounced winds (Ramstedt, Schöier & Olofsson 2009;Ferrarotti & Gail 2002;Kudritzki & Reimers 1978) and could inject FeH to the ISM. The presence of FeH in S stars and M giants is discussed in Wing (1972); Nordh, Lindgren & Wing (1977); Clegg & Lambert (1978); Lambert (1988); Hirai & Chinami (1992). Mould & Wyckoff (1978) calculated column densities of FeH for several models of stellar atmospheres for S and M stars.…”

Section: Astrophysical Originmentioning

confidence: 99%

Missing Fe: hydrogenated iron nanoparticles

Bilalbegović

Maksimović

Mohaček-Grošev

2016

Monthly Notices of the Royal Astronomical Society: Letters

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Although it was found that the FeH lines exist in the spectra of some stars, none of the spectral features in the ISM have been assigned to this molecule. We suggest that iron atoms interact with hydrogen and produce Fe-H nanoparticles which sometimes contain many H atoms. We calculate infrared spectra of hydrogenated iron nanoparticles using density functional theory methods and find broad, overlapping bands. Desorption of H 2 could induce spinning of these small Fe-H dust grains. Some of hydrogenated iron nanoparticles posses magnetic and electric moments and should interact with electromagnetic fields in the ISM. Fe n H m nanoparticles could contribute to the polarization of the ISM and the anomalous microwave emission. We discuss the conditions required to form FeH and Fe n H m in the ISM.

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Section: Astrophysical Originmentioning

confidence: 99%

Missing Fe: hydrogenated iron nanoparticles

Bilalbegović

Maksimović

Mohaček-Grošev

2016

Monthly Notices of the Royal Astronomical Society: Letters

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“…In the method of wavelength coincidence, the procedure of identification is completed as the list of accurate wavelengths for a particular transition of the selected molecule and the stellar spectrum are compared for coincidences (Hansen 1985;Lambert 1988). The method of coincidence assumes an identification of the solar line with a laboratory line if the line is located within 0.05 cm −1 of the listed laboratory value.…”

Section: Feh Solar Identificationmentioning

confidence: 99%

“…All known FeH bands (Phillips et al 1987) within the spectral range of the present umbral spectrum were checked with this procedure (Fawzy 1995). A slightly different version of this method was developed and used by Lambert (1988). Figure 1 shows a good example of the coincidence curve for the transition (1/2−1/2) of the lower (a) energy level of the Λ-doublet pair for the R-branch of the FeH (0−0) band.…”

Section: Feh Solar Identificationmentioning

confidence: 99%

Identification of FeH molecular lines in the spectrum of a sunspot umbra

Fawzy

Youssef

Engvold

1998

Astron. Astrophys. Suppl. Ser.

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“…Later Wing et al (1977) and Wohl et al (1983) showed that there was no evidence for other FeH bands in the infrared photospheric spectrum (these IR bands are well present in sunspot spectra). Their conclusion is that the blue and green FeH bands are very probably absent in the photospheric spectrum (see Lambert, 1988, for a review of the FeH identification). Table 1 summarizes the different molecular transitions identified in the ultraviolet and visible parts of the solar photospheric spectrum (see , for a similar table relative to the infrared part of the solar spectrum).…”

Section: Referencesmentioning

confidence: 99%

Molecules in the Sun and Molecular Data

Grevesse

Sauval

1994

International Astronomical Union Colloquium

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Molecules play a unique role in solar spectroscopy in allowing to derive, with high accuracy, the temperature structure of the photospheric layers from where the solar spectrum in the near ultraviolet, visible and infrared emerges. They also allow to observe the heterogeneous structure of the outer layers as well as the subtle convective motions in the layers just above the solar convection zone. Molecules play also a unique role in defining the solar chemical composition, at least as far as the very important elements like carbon, nitrogen and oxygen are concerned. They also offer the unique opportunity to derive meaningful isotopic ratios for C and O. Although we shall not deal with sunspots in the present review, it has to be recalled that molecules are the only tracers to derive the solar abundances of CI and F from the rotation-vibration lines of HC1 and HF present in the infrared sunspot spectra (Hall & Noyes 1972; Hall & Noyes 1969).On the other hand, the Sun itself offers a unique opportunity to produce molecular transitions, in local thermodynamic equilibrium (LTE), at rather high temperatures (T ∼ 5000 K), higher in any case than in the laboratory, often in non LTE (see review by Johnson in this volume). Therefore, new lines and new transitions of higher excitation appear in the solar spectrum allowing to use the Sun as a “permanent laboratory source” in order to refine the molecular constants. Furthermore, the solar photosphere, where we believe the physical conditions and physical processes are better known than in any other stars, offers a unique possiblity to test basic molecular data like dissociation energies and transition probabilities.

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On the identification of molecules in the cool carbon stars

Abstract: This paper discusses some problems encountered in identifying molecular lines in the rich spectra of cool carbon and related stars. Three molecules-FeH, ZrS, and CN-are reviewed.

Cited by 11 publications

References 25 publications

Missing Fe: hydrogenated iron nanoparticles

Missing Fe: hydrogenated iron nanoparticles

Identification of FeH molecular lines in the spectrum of a sunspot umbra

Molecules in the Sun and Molecular Data

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