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J/A+A/606/A50   Fe-rich silicate analogues mass absorption coeff. (Demyk+, 2017)

Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues. II: Mg and Fe-rich amorphous silicates Demyk K., Meny C., Leroux H., Depecker C., Brubach J.-B., Roy P., Nayral C., Ojo W.-S., Delpech F. <Astron. Astrophys. 606, A50 (2017)> =2017A&A...606A..50D (SIMBAD/NED BibCode)
ADC_Keywords: Spectra, infrared ; Interstellar medium Keywords: dust, extinction - submillimeter: ISM - infrared: ISM - methods: laboratory: solid state - astrochemistry - Abstract: To model the cold dust emission observed in the diffuse interstellar medium, in dense molecular clouds or in cold clumps that could eventually form new stars, it is mandatory to know the physical and spectroscopic properties of this dust and to understand its emission. This work is a continuation of previous studies aiming at providing astronomers with spectroscopic data of realistic cosmic dust analogues for the interpretation of observations. The aim of the present work is to extend the range of studied analogues to iron-rich silicate dust analogues. Ferromagnesium amorphous silicate dust analogues were produced by a sol-gel method with a mean composition close to Mg1-xFexSiO3 with x=0.1, 0.2, 0.3, 0.4. Part of each sample was annealed at 500°C for two hours in a reducing atmosphere to modify the oxidation state of iron. We have measured the mass absorption coefficient (MAC) of these eight ferromagnesium amorphous silicate dust analogues in the spectral domain 30-1000um for grain temperature in the range 10-300K and at room temperature in the 5-40um range. The MAC of ferromagnesium samples behaves in the same way as the MAC of pure Mg-rich amorphous silicate samples. In the 30-300K range, the MAC increases with increasing grain temperature whereas in the range 10-30K, we do not see any change of the MAC. The MAC cannot be described by a single power law in λ. The MAC of the samples does not show any clear trend with the iron content. However the annealing process has, on average, an effect on the MAC that we explain by the evolution of the structure of the samples induced by the processing. The MAC of all the samples is much higher than the MAC calculated by dust models. The complex behavior of the MAC of amorphous silicates with wavelength and temperature is observed whatever the exact silicate composition (Mg vs. Fe amount). It is a universal characteristic of amorphous materials, and therefore of amorphous cosmic silicates, that should be taken into account in astronomical modeling. The enhanced MAC of the measured samples compared to the MAC calculated for cosmic dust model implies that dust masses are overestimated by the models. Description: The data available here are part of the Database STOPCODA where they can be retrieved too (SpecTroscopy and Optical Properties of Cosmic Dust Analogues, https://sshade.eu). See also https://blog.sshade.eu/. They contain the mass absorption coefficient of cosmic dust analogues in the spectral domain 5-1000microns and in the temperature range 300-10K. The cosmic dust analogues are amorphous silicates of composition Mg1-xFexSiO3 with x=0.1, 0.2, 0.3, 0.4. The first column is the wavenumber in cm-1, the second column is the mass absorption coefficient in cm2/g. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file e10-10k.dat 32 3031 MAC E10 10K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron dominant) e10-30k.dat 32 3031 MAC E10 30K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron dominant) e10-100k.dat 32 3031 MAC E10 100K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron dominant) e10-200k.dat 32 3031 MAC E10 200K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron dominant) e10-300k.dat 32 3031 MAC E10 300K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron dominant) e10r10k.dat 32 3018 MAC E10R 10K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron reduced) e10r30k.dat 32 3018 MAC E10R 30K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron reduced) e10r100k.dat 32 3018 MAC E10R 100K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron reduced) e10r200k.dat 32 3018 MAC E10R 200K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron reduced) e10r300k.dat 32 3018 MAC E10R 300K (amorphous sample of composition Mg0.9Fe0.1SiO3, 10% iron, ferric iron reduced) e20-10k.dat 32 2861 MAC E20 10K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron dominant) e20-30k.dat 32 2861 MAC E20 30K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron dominant) e20-100k.dat 32 2861 MAC E20 100K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron dominant) e20-200k.dat 32 2861 MAC E20 200K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron dominant) e20-300k.dat 32 2861 MAC E20 300K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron dominant) e20r10k.dat 32 2800 MAC E20R 10K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron reduced) e20r30k.dat 32 2800 MAC E20R 30K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron reduced) e20r100k.dat 32 2800 MAC E20R 100K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron reduced) e20r200k.dat 32 2800 MAC E20R 200K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron reduced) e20r300k.dat 32 2800 MAC E20R 300K (amorphous sample of composition Mg0.8Fe0.2SiO3, 20% iron, ferric iron reduced) e30-10k.dat 32 2490 MAC E30 10K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron dominant) e30-30k.dat 32 2490 MAC E30 30K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron dominant) e30-100k.dat 32 2490 MAC E30 100K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron dominant) e30-200k.dat 32 2490 MAC E30 200K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron dominant) e30-300k.dat 32 2490 MAC E30 300K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron dominant) e30r10k.dat 32 2496 MAC E30R 10K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron reduced) e30r30k.dat 32 2496 MAC E30R 30K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron reduced) e30r100k.dat 32 2496 MAC E30R 100K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron reduced) e30r200k.dat 32 2496 MAC E30R 200K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron reduced) e30r300k.dat 32 2496 MAC E30R 300K (amorphous sample of composition Mg0.7Fe0.3SiO3, 30% iron, ferric iron reduced) e40-10k.dat 32 2496 MAC E40 10K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron dominant) e40-30k.dat 32 2496 MAC E40 30K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron dominant) e40-100k.dat 32 2496 MAC E40 100K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron dominant) e40-200k.dat 32 2496 MAC E40 200K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron dominant) e40-300k.dat 32 2496 MAC E40 300K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron dominant) e40r10k.dat 32 2496 MAC E40R 10K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron reduced) e40r30k.dat 32 2496 MAC E40R 30K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron reduced) e40r100k.dat 32 2496 MAC E40R 100K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron reduced) e40r200k.dat 32 2496 MAC E40R 200K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron reduced) e40r300k.dat 32 2496 MAC E40R 300K (amorphous sample of composition Mg0.6Fe0.4SiO3, 40% iron, ferric iron reduced)
Byte-by-byte Description of file (# headlines): e*.dat
Bytes Format Units Label Explanations
4- 16 E13.8 cm-1 Wavenumber Wavenumber 20- 32 E13.8 cm+2/g MAC Mass absorption coefficient
Acknowledgements: Karine Demyk, karine.demyk(at)irap.omp.eu
(End) Karine Demyk [IRAP], Patricia Vannier [CDS] 02-Oct-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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