Contact Astronomy: Comet Dust

2012 ◽  
pp. 75-82
Author(s):  
Giovanni F. Bignami
Keyword(s):  
Author(s):  
D.E. Brownlee ◽  
A.L. Albee

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.


1996 ◽  
Vol 150 ◽  
pp. 497-506
Author(s):  
J. Mayo Greenberg ◽  
Aigen Li ◽  
Tetsuo Yamamoto ◽  
Takashi Kozasa
Keyword(s):  

AbstractThe effects of preaggregation silicate crystallinity and postaggregation silicate crystallinity on the 11.3μm structure in comet dust emission have been calculated. Of the order of 10 - 20% crystallinity provides the best agreement to date with observation but the fits are not yet fully satisfactory.


2005 ◽  
Vol 13 ◽  
pp. 485-487 ◽  
Author(s):  
Hiroshi Kimura ◽  
Ingrid Mann

AbstractTo better understand the processing of pristine materials in comets, we compare the composition of cometary and interstellar dust. We suggest that the deficit of N in comet dust bears evidence for the processing of the organic refractory mantle of pre-solar interstellar dust, unless it arises from the protosolar disk chemistry. The amorphous silicate core, in contrast, seems to be protected against processing due to the presence of the organic refractory mantle.


2020 ◽  
Author(s):  
Qasim Afghan ◽  
Geraint H. Jones ◽  
Oliver Price

<p>The fine-structure detail of several comet dust tails is analysed from amateur and professional comet images using the Finson-Probstein mdoel. Given the date and time of the image taken, the comet’s position in the sky is calculated using an open source algorithm [1] and the comet’s dust tail is simulated for that position and time. This modeled dust tail structure is then projected and overlaid onto the comet image to directly compare and identify similarities and discrepancies between the model and the image. Using the novel analysis method of mapping the image to a dust grain beta against ejection time plot [2], tail structures can be more easily identified and analysed. This also allows for the tracking of tail structure over time, as images of a single comet from different times and observatories can be mapped onto the same plot. This method compensates for the difficulties of investigating tail structures in images as the comet moves across the image and as viewing geometry changes over time.      </p> <p>This is a continuation of the work done previously on Comet C/2006 P1 (McNaught), which ultimately led to the observation of the formation processes of new fine-scale structure features in the comet’s dust tail [2]. This model is now applied to several other comets, including the recent Comet ATLAS (C/2019 Y4), to map their tail structures and to highlight this model’s utility in comet dust tail analysis.</p> <p>Finally, this work will be put into context as the first step in the development of an automated analysis method for cometary dust and ion tails. This automated method is in preparation for the upcoming opening of the Vera Rubin Observatory (LSST), and aims to automatically identify comet tail structures from the Observatory’s stream of comet images. The robustness of this analysis suite enables it to also be implemented on amateur comet images, making use of the abundant and valuable data from amateur astronomers.</p> <p> </p> <p> </p> <p> </p> <p> </p> <p>[1] Lang, Dustin, David W. Hogg, Keir Mierle, Michael Blanton, and Sam Roweis. 2010. "ASTROMETRY.NET: BLIND ASTROMETRIC CALIBRATION OF ARBITRARY ASTRONOMICAL IMAGES". The Astronomical Journal 139 (5): 1782-1800. doi:10.1088/0004-6256/139/5/1782.</p> <p>[2] Price, Oliver, Geraint H. Jones, Jeff Morrill, Mathew Owens, Karl Battams, Huw Morgan, Miloslav Drückmuller, and Sebastian Deiries. 2019. "Fine-Scale Structure In Cometary Dust Tails I: Analysis Of Striae In Comet C/2006 P1 (Mcnaught) Through Temporal Mapping". Icarus 319: 540-557. doi:10.1016/j.icarus.2018.09.013.</p>


Nature ◽  
1990 ◽  
Vol 348 (6297) ◽  
pp. 157-160 ◽  
Author(s):  
Kevin Zahnle ◽  
David Grinspoon
Keyword(s):  

1984 ◽  
Vol 4 (9) ◽  
pp. 211-212 ◽  
Author(s):  
J.Mayo Greenberg
Keyword(s):  

2011 ◽  
Vol 742 (2) ◽  
pp. 86 ◽  
Author(s):  
Robert O. Pepin ◽  
Russell L. Palma ◽  
Robert D. Gehrz ◽  
Sumner Starrfield

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