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

Fawzy, Diaa E.; Youssef, N. H.; Engvold, O.

doi:10.1051/aas:1998196

Cited by 10 publications

(4 citation statements)

References 6 publications

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“…For all the advantages of FTS devices, their poor efficiency renders them essentially useless for precise stellar velocimetry. As a result of this limited sensitivity, FTSs are commonly used only in situations where sensitivity can be sacrificed for precision, such as laboratory spectroscopy (Kerber et al 2006;Aldenius, Johansson, & Murphy 2006;Ying et al 2005), solar observations (Fawzy, Youssef, & Engvold 1998), or where very high spectral resolution or accurate wavelength calibration are required, such as in measurements of planetary atmospheres (Cooper et al 2001;Krasnopolsky, Maillard, & Owen 2004).…”

Section: Introductionmentioning

confidence: 99%

Initial Results from the USNO Dispersed Fourier Transform Spectrograph

Hajian

Behr

Cenko

et al. 2007

ApJ

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We have designed and constructed a ''dispersed Fourier transform spectrometer'' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity disadvantage of a conventional FTS for high-resolution, broadband, optical spectroscopy, while preserving many of the advantages inherent to interferometric spectrometers. In addition, we have implemented a simple and inexpensive laser metrology system, which enables very precise calibration of the interferometer wavelength scale. The fusion of interferometric and dispersive technologies with a laser metrology system yields an instrument well suited to stellar spectroscopy, velocimetry, and extrasolar planet detection, which is competitive with existing high-resolution, high-accuracy stellar spectrometers. In this paper we describe the design of our prototype dFTS, explain the algorithm we use to efficiently reconstruct a broadband spectrum from a sequence of narrowband interferograms, and present initial observations and resulting velocimetry of stellar targets.

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Section: Introductionmentioning

confidence: 99%

Initial Results from the USNO Dispersed Fourier Transform Spectrograph

Hajian

Behr

Cenko

et al. 2007

ApJ

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“…As a reference and a test, we cross-correlated a computed spectrum from this theoretical line list, which is broadened by an instrumental profile with a resolving power of 70 000, with the original line list (e.g. Fawzy 1995;Fawzy et al 1998). To be specific, we varied the theoretical positions with steps of Δσ = 0.0125 Å in a range of 0.375 Å and measured the relative intensity at the different positions weighted with W λ of the line and integrate over all lines.…”

Section: Cross-correlation Methodsmentioning

confidence: 99%

CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf

Wende

Reiners

Seifahrt

et al. 2010

A&A

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Molecular FeH provides a large number of sharp and isolated absorption lines that can be used to measure radial velocity, rotation, or magnetic field strength with high accuracy. Our aim is to provide an FeH atlas for M-type stars in the spectral region from 986 nm to 1077 nm (Wing-Ford band). To identify these lines in CRIRES spectra of the magnetically inactive, slowly rotating, M5.5 dwarf GJ1002, we calculated model spectra for the selected spectral region with theoretical FeH line data. In general this line list agrees with the observed data, but several individual lines differ significantly in position or in line strength. After identification of as many as possible FeH lines, we corrected the line data for position and line strength to provide an accurate atlas of FeH absorption lines for use in high precision spectroscopy of low mass stars. For all lines, we used a Voigt function to obtain their positions and equivalent widths. Identification with theoretical lines was done by hand. For confirmation of the identified lines, we used statistical methods, cross-correlation techniques, and line intensities. Eventually, we were able to identify FeH lines from the (0, 0), (1, 0), (1, 1), (2, 1), (2, 2), (3, 2), and (4, 3) vibrational bands in the observed spectra and correct the positions of the lines if necessary. The deviations between theoretical and observed positions follow a normal distribution approximately around zero. In order to empirically correct the line strength, we determined T eff , instrumental broadening (rotational broadening) and a van der Waals enhancement factor for the FeH lines in GJ1002. We also give the scaling factors for the Einstein A values to correct the line strengths. With the identified lines, we derived rotational temperatures from the line intensities for GJ1002. We conclude that FeH lines can be used for a wide variety of applications in astrophysics. With the identified lines it will be possible for example to characterize magnetically sensitive or very temperature sensitive lines, which can be used to investigate M-type stars.

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“…[18][19][20][21][22] This allowed the identifi cation of Fe(I) derivatives in astrophysical sources, such as in the atmosphere of stars and in sunspots. [23][24][25][26] The generation of "pure" RFe(I) complexes remains a very diffi cult task. Only a very few RFe radicals have been isolated.…”

Section: Introductionmentioning

confidence: 99%

The Generation of Neutral Derivatives of Low-Valence Iron, RFe(I), by Netralization—Reionization Mass Spectrometry

Zagorevski

2005

Eur J Mass Spectrom (Chichester)

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Neutralization-reionization mass spectrometry is applied for the generation of low-valence iron derivatives. Neutralization of Rfe(+) (R=H, F, Cl, Br, I, CN, OH, NH(2), acac, C(6)H(5)) ions resulted in the corresponding neutrals having lifetimes of at least 5 micros. Atom connectivities in RFe ions and neutrals were elucidated by a variety of tandem mass spectrometry techniques. The present study provides the first experimental evidence of the intrinsic stability of neutral IFe, NCFe, acacFe and C(6)H(5)Fe.

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

Cited by 10 publications

References 6 publications

Initial Results from the USNO Dispersed Fourier Transform Spectrograph

Initial Results from the USNO Dispersed Fourier Transform Spectrograph

CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf

The Generation of Neutral Derivatives of Low-Valence Iron, RFe(I), by Netralization—Reionization Mass Spectrometry

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