Silicon Depletion in the Interstellar Medium

Haris, U.; Parvathi, V. S.; Gudennavar, S. B.; Bubbly, S. G.; Murthy, Jayant; Sofia, U. J.

doi:10.3847/0004-6256/151/6/143

Cited by 12 publications

(39 citation statements)

References 30 publications

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“…The nondetection of scattering and the stable peak wavelength imply that the carrier of the 2175Å bump is sufficiently small (i.e., nano-sized) to be in the Rayleigh limit (Mathis 1994). If the 2175Å bump is indeed related to silicate grains as suggested by Duley (1985), Steel & Duley (1987) and Haris et al (2016), there would exist a population of nano-sized silicate grains in the diffuse ISM.…”

Section: Introductionmentioning

confidence: 99%

“…General results concerning scattering by small particles indicate that the far-UV extinction arises from nano-sized grains (see Draine 1995), although the exact sizes of these grains can not be constrained by the far-UV extinction (see Wang et al 2015). Therefore, the correlation between the silicon depletion and the far-UV extinction rise derived by Haris et al (2016) also implies the existence of an appreciable number of nano silicate grains in the diffuse ISM.…”

Section: Introductionmentioning

confidence: 99%

“…Resultantly, we arrive at a sample of 46 sightlines (see Table 1) which is a subsample of the 131 sightlines of Haris et al (2016). For each sightline, we take the [Si/H] gas abundance from Haris et al (2016) and the extinction parameters c ′ j (j = 1, 2, 3, 4), x o and γ (see below) from Jenniskens & Greenberg (1993), Valencic et al (2004), Lewis et al (2005), and Gordon et al (2009).…”

Section: The Samplementioning

confidence: 99%

“…Assuming the interstellar abundance of silicon to be solar (i.e., [Si/H] ISM = [Si/H] ⊙ ), they derived the silicon depletion (i.e., [Si/H] dust = [Si/H] ISM − [Si/H] gas ) for each sightline. Haris et al (2016) further examined the UV extinction curves of 16 sightlines (of these 131 sightlines) and explored the relation between the silicon depletion and the 2175Å extinction bump as well as the far-UV extinction rise. Although the derived Pearson correlation coefficients (R ≈ −0.42 for the silicon depletion and the 2175Å bump, and R ≈ −0.32 for the silicon depletion and the far-UV rise) are by no means substantial, they claimed that the silicon depletion positively "correlates" with the 2175Å bump and the far-UV extinction rise.…”

Section: Introductionmentioning

confidence: 99%

“…Very recently, Haris et al (2016) determined the gas-phase abundance of silicon ([Si/H] gas ) for 131 Galactic sightlines using archival data. Assuming the interstellar abundance of silicon to be solar (i.e., [Si/H] ISM = [Si/H] ⊙ ), they derived the silicon depletion (i.e., [Si/H] dust = [Si/H] ISM − [Si/H] gas ) for each sightline.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Interstellar Silicon Depletion and the Ultraviolet Extinction

Mishra

2017

ApJ

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Spinning small silicate grains were recently invoked to account for the Galactic foreground anomalous microwave emission. These grains, if present, will absorb starlight in the far ultraviolet (UV). There is also renewed interest in attributing the enigmatic 2175Å interstellar extinction bump to small silicates. To probe the role of silicon in the UV extinction, we explore the relations between the amount of silicon required to be locked up in silicates [Si/H] dust and the 2175Å bump or the far-UV extinction rise, based on an analysis of the extinction curves along 46 Galactic sightlines for which the gas-phase silicon abundance [Si/H]

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: The Samplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interstellar Silicon Depletion and the Ultraviolet Extinction

Mishra

2017

ApJ

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Silicon Chemistry in the Interstellar Medium and Circumstellar Envelopes

Job,

Thirumoorthy

2024

ACS Earth Space Chem.

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The molecules comprising the main group elements in lower valency are identified in the interstellar medium. Silicon is the fifth most abundant trace element, associated with late-type stars and regions where stars are developing, and plays a crucial role in forming interstellar dust grains. In the recent past, integrated experimental and computational strategies in silicon chemistry have become increasingly popular, and researchers have identified several Si-bearing molecules in the interstellar medium and circumstellar envelopes. About 300 molecules are observed in the interstellar medium and circumstellar envelopes in total, of which 15 are Si-bearing molecules. In addition, 28 Si-bearing chains and rings are reported as potential candidates for astronomical detection. This review summarizes the available data on the astronomical aspects of Si-bearing molecules. Detailed investigation of Si-bearing molecules commonly found in star-forming areas, late-type stars, and their relevance in space have been well documented here. Finally, attention is drawn to potential Si-bearing molecules for future interstellar identification, which has been reported using experimental and quantum chemical approaches.

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The essential elements of dust evolution

Jones

Ysard

2019

A&A

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Context. There remain many open questions relating to the depletion of elements into dust, e.g., exactly how are C and O incorporated into dust in dense clouds and, in particular, what drives the disappearance of oxygen in the denser interstellar medium? Aims. This work is, in part, an attempt to explain the apparently anomalous incorporation of O atoms into dust in dense clouds. Methods. We re-visit the question of the depletion of the elements incorporated into the carbonaceous component of interstellar dust, i.e., C, H, O, N and S, in the light of recent analyses of the organics in comets, meteorites and interplanetary dust particles. Results. We find that oxygen could be combined with ≈10–20 % of the carbon in the dust in dense regions in the form of a difficult to observe, organic carbonate, (−O−O>C =O), which could explain the unaccounted for 170–255 ppm oxygen depletion. Conclusions. We conclude that, while C, O and N atoms are depleted into an amorphous a-C:H:O:N phase, we posit that a significant fraction of C and O atoms could be sequestered into an organic carbonate, which provides a viable solution to the oxygen depletion problem. Further, the thermal or photolytic decomposition of this carbonate may have a bearing on the formation of CO2 in the ISM.

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Silicon Depletion in the Interstellar Medium

Cited by 12 publications

References 30 publications

Interstellar Silicon Depletion and the Ultraviolet Extinction

Interstellar Silicon Depletion and the Ultraviolet Extinction

Silicon Chemistry in the Interstellar Medium and Circumstellar Envelopes

The essential elements of dust evolution

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