Mechanical Alignment of Prolate Cosmic‐Dust Grains: Cross Section Alignment

1996 ◽  
Vol 472 (1) ◽  
pp. 240-244 ◽  
Author(s):  
A.M. Lazarian ◽  
M. Efroimsky ◽  
J. Ozik
Keyword(s):  
Cross Section ◽  
Cosmic Dust ◽  
Mechanical Alignment ◽  
Dust Grains

Compositional in situ analysis of dusty material stemming from Saturn’s main rings

2021 ◽  
Author(s):  
Simon Linti ◽  
Jon Hillier ◽  
Christian Fischer ◽  
Hsiang-Wen Hsu ◽  
Mario Trieloff ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Impact Ionization ◽  
Source Region ◽  
Relative Sensitivity ◽  
Cosmic Dust ◽  
Dust Grains ◽  
Element Ratios ◽  
Sensitivity Factors ◽  
Compositional Diversity

<p>During the final mission phase, the Cassini spacecraft travelled through the gap between Saturn and its innermost D ring. One goal of these highly inclined orbits was sampling the dust population, mostly made of impact ejecta from the main rings, in the vicinity of the planet. These in situ measurements were primarily carried out by the Cosmic Dust Analyzer (CDA) onboard the spacecraft, which provided time-of-flight mass spectra of individual ice and dust grains, mostly between about 10 and 50 nm in size. Here we present an update on the composition of the silicate dust fraction stemming from Saturn’s main rings, which makes up about 30 % of the observed particles with water ice being the remaining fraction [1].</p> <p>Elemental analysis of the silicate spectra was performed using an updated deconvolution method, based on a technique originally applied to the interpretation of CDA interstellar dust measurements [2]. Neighboring spectral peaks due to mineral-forming ions such as Mg<sup>+</sup>, Al<sup>+</sup> and Si<sup>+</sup> are often unresolvable, because of CDA’s relatively low (m/dm = 20–50) mass resolution [3]. Therefore, application of a deconvolution technique is required to disentangle the peak interferences and derive valuable compositional information. The robustness of the applied method has been tested and optimized through comparison with an independent automated fit algorithm. In order to calculate elemental abundances within the particles, the derived ion abundances were combined with experimentally-determined relative sensitivity factors (RSFs) [4]. To provide context to the measured element ratios, we compared them with a variety of space-relevant materials. We find an overlap with chondritic material for Mg/Si and Fe/Mg ratios. The observed range within the element ratios, however, indicates the contribution of a variety of minerals such as olivine, plagioclase or pyroxenes. Although our results agree with realistic mineral compositions, the calculated abundances of Al<sup>+</sup> ions are still relatively uncertain and can be seen as an upper limit.</p> <p>Additionally, we present the results of a dynamical model, which allow us to derive the likely source region within the main rings of individually detected silicate grains. We find the C and B rings to be the most likely sources of the vast majority of grains with the D ring being only a minor source. Currently an analysis of compositional diversity between the different ring segments is under way.</p> <p> </p> <p><strong>References</strong></p> <p>[1] H.-W. Hsu et al. (2018) In situ collection of dust grains falling from Saturn’s rings into its atmosphere. Science 362.</p> <p>[2] N. Altobelli et al. (2016) Flux and composition of interstellar dust at Saturn from Cassini’s Cosmic Dust Analyzer. Science 352, 312–318.</p> <p>[3] R. Srama et al. (2004) The Cassini Cosmic Dust Analyzer. Space Science Reviews 114, 465–518.</p> <p>[4] K. Fiege et al. (2014) Calibration of relative sensitivity factors for impact ionization detectors with high-velocity silicate microparticles. Icarus 241, 336–345.</p>

Some Remarks on the Density of Interplanetary Dust Grains

1985 ◽  
Vol 85 ◽  
pp. 137-140
Author(s):  
P.L. Lamy
Keyword(s):  
Kinetic Energy ◽  
Bulk Density ◽  
Cross Section ◽  
Optical Sensors ◽  
Interplanetary Dust ◽  
Relevant Parameter ◽  
Dust Grains ◽  
Gravitational Forces ◽  
The Cross

AbstractThe relevance of the bulk density as a physical parameter characterizing interplanetary dust grains is discussed. The various measurements which lead to a determination of this parameter are reviewed. The specific case of the collected interplanetary dust grains is considered.The bulk density of interplanetary dust grains has been and is still a matter of controversy. This quantity cannot, in general, be directly measured; it is used to relate the mass and the size of a grain. This duality stems from physics itself as there are interactions sensitive to the mass (e.g., gravitational forces) while others are sensitive to the size or the cross-section (e.g., light scattering, radiation pressure, gas and plasma interactions). The measuring technics of the grains reflect this duality as, for instance, impact sensors are generally sensitive to the kinetic energy and thus to the mass, while optical sensors are sensitive to the cross-section. One sees that the density is not strictly speaking the relevant parameter, but what is needed is a relationship between mass and average cross-section.

scholarly journals Cosmic dust grains strike again

2000 ◽  
Vol 61 (8) ◽  
Author(s):  
Luis A. Anchordoqui
Keyword(s):  
Cosmic Dust ◽  
Dust Grains

scholarly journals The Photolysis of Aromatic Hydrocarbons Adsorbed on the Surfaces of Cosmic Dust Grains

2019 ◽  
Vol 63 (8) ◽  
pp. 633-641 ◽  
Author(s):  
M. S. Murga ◽  
V. N. Varakin ◽  
A. V. Stolyarov ◽  
D. S. Wiebe
Keyword(s):  
Aromatic Hydrocarbons ◽  
Cosmic Dust ◽  
Dust Grains

scholarly journals Laboratory Spectra of Amorphous and Crystalline Olivine: An Application to Comet Halley IR Spectrum

1991 ◽  
Vol 126 ◽  
pp. 125-128 ◽  
Author(s):  
A. Blanco ◽  
V. Orofino ◽  
E. Bussoletti ◽  
S. Fonti ◽  
L. Colangeli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Infrared Spectra ◽  
Ir Spectrum ◽  
Emission Feature ◽  
Cosmic Dust ◽  
Dust Grains ◽  
Natural Mineral ◽  
The Third ◽  
Different Types ◽  
Comet Halley

AbstractAmong the various silicates proposed as components of cosmic dust grains, olivine is considered one of the most likely materials. In this work we present the infrared spectra of three different types of olivine grains: crystalline, amorphous and synthetic (also amorphous). While the first and second sample derive from the same natural mineral, the third one has been prepared in the laboratory according to the relative cosmic abundances of the elements. The experimental data are used to fit the emission feature observed in the comet Halley spectrum between 8 and 13μm.Satisfactory results are obtained by using synthetic olivine mixed with a small amount (5%) of crystalline grains.

Orientation of cosmic dust grains

1976 ◽  
Vol 43 (2) ◽  
pp. 291-317 ◽  
Author(s):  
A. Z. Dolginov ◽  
I. G. Mytrophanov
Keyword(s):  
Cosmic Dust ◽  
Dust Grains

Ion implantation effects in “cosmic” dust grains

1974 ◽  
Vol 22 (3) ◽  
pp. 205-214 ◽  
Author(s):  
J.P. Bibring ◽  
Y. Langevin ◽  
M. Maurette ◽  
R. Meunier ◽  
B. Jouffrey ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Cosmic Dust ◽  
Dust Grains
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