Correction to the Updated Edlén Equation for the Refractive Index of Air

Birch, K. G.; Downs, M J

doi:10.1088/0026-1394/31/4/006

Cited by 376 publications

(184 citation statements)

References 2 publications

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“…The air wavelengths in Table 1 have been determined with the Edlén (1966) equation, and include the more recent update for the refractive index of air, Eq. (3) in Birch & Downs (1994). All lines measured in this work have a peak signal to noise ratio of more than 100, and the BF uncertainties are dominated by the tungsten lamp calibration uncertainty and the uncertainty in the intensity calibration "cross-over" between the two spectral regions.…”

Section: Introductionmentioning

confidence: 80%

Infrared Mn i laboratory oscillator strengths for the study of late type stars and ultracool dwarfs

Blackwell-Whitehead

Pavlenko

Nave

et al. 2010

A&A

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Aims. The aim of our new laboratory measurements is to measure accurate absolute oscillator strengths for neutral manganese transitions in the infrared needed for the study of late-type stars and ultracool dwarfs. Methods. Branching fractions have been measured by high resolution Fourier transform spectroscopy and combined with radiative level lifetimes in the literature to yield oscillator strengths.Results. We present experimental oscillator strengths for 20 Mn i transitions in the wavelength range 3216 to 13 997 Å, 15 of which are in the infrared. The transitions at 12 899 Å and 12 975 Å are observed as strong features in the spectra of late-type stars and ultracool dwarfs. We have fitted our calculated spectra to the observed Mn i lines in spectra of late-type stars. Using the new experimentally measured Mn i log(g f ) values together with existing data for Mn i hyperfine structure splitting factors we determined the manganese abundance to be log N(Mn) = −6.65 ± 0.05 in the atmosphere of the Sun, log N(Mn) = 6.95 ± 0.20 in the atmosphere of Arcturus, and log N(Mn) = −6.70 ± 0.20 in the atmosphere of M 9.5 dwarf 2MASSW 0140026+270150.

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Section: Introductionmentioning

confidence: 80%

Infrared Mn i laboratory oscillator strengths for the study of late type stars and ultracool dwarfs

Blackwell-Whitehead

Pavlenko

Nave

et al. 2010

A&A

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“…uum wavelength conversion as VALD3 1 . The conversion from λ vac to λ air , taken from Birch & Downs (1994), applies to dry air at 1 atm pressure and 15 • C with 0.045% CO 2 by volume, and is as follows:…”

Section: Parametric Cross-matchmentioning

confidence: 99%

The Belgian repository of fundamental atomic data and stellar spectra (BRASS)

Laverick

Lobel

Merle

et al. 2018

A&A

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Context. Fundamental atomic parameters, such as oscillator strengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work underway to produce these parameters for many astrophysically important ions, uncertainties in these parameters remain large and can propagate throughout the entire field of astronomy. Aims. The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide the largest systematic and homogeneous quality assessment of atomic data to date in terms of wavelength, atomic and stellar parameter coverage. To prepare for it, we first compiled multiple literature occurrences of many individual atomic transitions, from several atomic databases of astrophysical interest, and assessed their agreement. In a second step synthetic spectra will be compared against extremely highquality observed spectra, for a large number of BAFGK spectral type stars, in order to critically evaluate the atomic data of a large number of important stellar lines. Methods. Several atomic repositories were searched and their data retrieved and formatted in a consistent manner. Data entries from all repositories were cross-matched against our initial BRASS atomic line list to find multiple occurrences of the same transition. Where possible we used a new non-parametric cross-match depending only on electronic configurations and total angular momentum values. We also checked for duplicate entries of the same physical transition, within each retrieved repository, using the non-parametric cross-match. Results. We report on the number of cross-matched transitions for each repository and compare their fundamental atomic parameters. We find differences in log(g f ) values of up to 2 dex or more. We also find and report that ∼2% of our line list and Vienna Atomic Line Database retrievals are composed of duplicate transitions. Finally we provide a number of examples of atomic spectral lines with different retrieved literature log(g f ) values, and discuss the impact of these uncertain log(g f ) values on quantitative spectroscopy. All cross-matched atomic data and duplicate transition pairs are available to download at brass.sdf.org.

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“…Generally, it can be calculated from the measured environmental parameters such as temperature, ambient pressure and relative humidity on the basis of mathematical models such as the Edlen's formula [1][2][3] or other alternative formulae proposed by Ciddor or by Bonsch and Potulski [4,5]. A relative accuracy of the order of 10 -7 on the refractive index (which means an accuracy of 0.1 °C on temperature) is quite easily achievable for short distances in controlled environment, while in case of measurement of long distances this level of accuracy is still a challenge [6][7][8].…”

Section: Aim Of the Researchmentioning

confidence: 99%

Air temperature measurements based on the speed of sound to compensate long distance interferometric measurements

Astrua

Pisani

Zucco

2014

EPJ Web of Conferences

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Abstract.A method to measure the real time temperature distribution along an interferometer path based on the propagation of acoustic waves is presented. It exploits the high sensitivity of the speed of sound in air to the air temperature. In particular, it takes advantage of a special set-up where the generation of the acoustic waves is synchronous with the amplitude modulation of a laser source. A photodetector converts the laser light to an electronic signal considered as reference, while the incoming acoustic waves are focused on a microphone and generate a second signal. In this condition, the phase difference between the two signals substantially depends on the temperature of the air volume interposed between the sources and the receivers. The comparison with the traditional temperature sensors highlighted the limit of the latter in case of fast temperature variations and the advantage of a measurement integrated along the optical path instead of a sampling measurement. The capability of the acoustic method to compensate the interferometric distance measurements due to air temperature variations has been demonstrated for distances up to 27 m.

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Correction to the Updated Edlén Equation for the Refractive Index of Air

Cited by 376 publications

References 2 publications

Infrared Mn i laboratory oscillator strengths for the study of late type stars and ultracool dwarfs

Infrared Mn i laboratory oscillator strengths for the study of late type stars and ultracool dwarfs

The Belgian repository of fundamental atomic data and stellar spectra (BRASS)

Air temperature measurements based on the speed of sound to compensate long distance interferometric measurements

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