Iron: A Key Element for Understanding the Origin and Evolution of Interstellar Dust

Dwek, Eli

doi:10.3847/0004-637x/825/2/136

Cited by 88 publications

(90 citation statements)

References 72 publications

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“…Iron could be present in the dust grains in the form of metallic iron or FeS inclusions, as can be observed in the presolar glass with embedded metal and sulfides (GEMS, Bradley 1994) in porous interplanetary dust particles (IDPs). Based on elemental depletion observations and on the modeling of the dust formation, Dwek (2016) proposed that iron exists in metallic form either as inclusions or as separate iron grains. Iron has also been proposed to be present as a population of iron oxide grains (magnetite, Fe 3 O 4 , or maghemite, γ-Fe 2 O 3 ) (Draine & Hensley 2013) or as iron oxide inclusions in the silicate grains.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues

Demyk

Meny

Leroux

et al. 2017

A&A

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Context. 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. Aims. 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. Methods. Ferromagnesium amorphous silicate dust analogues were produced by a sol-gel method with a mean composition close to Mg 1−x Fe x SiO 3 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 30−1000 µm for grain temperature in the range 10−300 K and at room temperature in the 5−40 µm range. Results. The MAC of ferromagnesium samples behaves in the same way as the MAC of pure Mg-rich amorphous silicate samples. In the 30−300 K range, the MAC increases with increasing grain temperature whereas in the range 10−30 K, we do not see any change of the MAC. The MAC cannot be described by a single power law in λ −β . 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. Conclusions. 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.

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Section: Introductionmentioning

confidence: 99%

Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues

Demyk

Meny

Leroux

et al. 2017

A&A

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“…It was suggested that PAHs and grains reform in the ISM. An efficient process is condensation on already existing grains (Jones et al 1994;Dwek 2016). Similar mechanisms play a role in the destruction and replenishment of hydrogenated iron nanoparticles.…”

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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“…Notably, SNe Ia are thought to have produced approximately two thirds of the Fe present in our Galaxy today (Dwek, 2016), the other third coming from CCSNe. CCSNe originate from massive stars and explode rather promptly after star-formation, whereas SNe Ia also arise in old stellar populations, which results in a "delayed" enrichment of the interstellar medium by SNe Ia.…”

Section: Direct and Indirect Observable Signatures Of Nucleosynthesismentioning

confidence: 99%

Nucleosynthesis in Thermonuclear Supernovae

Seitenzahl¹,

Townsley²

2017

Handbook of Supernovae

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The explosion energy of thermonuclear (Type Ia) supernovae is derived from the difference in nuclear binding energy liberated in the explosive fusion of light "fuel" nuclei, predominantly carbon and oxygen, into more tightly bound nuclear "ash" dominated by iron and silicon group elements. The very same explosive thermonuclear fusion event is also one of the major processes contributing to the nucleosynthesis of the heavy elements, in particular the iron-group elements. For example, most of the iron and manganese in the Sun and its planetary system was produced in thermonuclear supernovae. Here, we review the physics of explosive thermonuclear burning in carbon-oxygen white dwarf material and the methodologies utilized in calculating predicted nucleosynthesis from hydrodynamic explosion models. While the dominant explosion scenario remains unclear, many aspects of the nuclear combustion and nucleosynthesis are common to all models and must occur in some form in order to produce the observed yields. We summarize the predicted nucleosynthetic yields for existing explosions models, placing particular emphasis on characteristic differences in the nucleosynthetic signatures of the different suggested scenarios leading to Type Ia supernovae. Following this, we discuss how these signatures compare with observations of several individual supernovae, remnants, and the composition of material in our Galaxy and galaxy clusters.

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Iron: A Key Element for Understanding the Origin and Evolution of Interstellar Dust

Cited by 88 publications

References 72 publications

Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues

Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues

Missing Fe: hydrogenated iron nanoparticles

Nucleosynthesis in Thermonuclear Supernovae

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