Science > Physics > Interplanetary dust detected by the Cassini CDA Chemical Analyser
| Topic: |
Science > Physics |
| User: |
"ayaz" |
| Date: |
17 Jan 2008 06:26:51 PM |
| Object: |
Interplanetary dust detected by the Cassini CDA Chemical Analyser |
http://www.sciencedirect.com/science?_ob=3DArticleURL&_udi=3DB6WGF-4NHM589-C=
&_user=3D10&_rdoc=3D1&_fmt=3D&_orig=3Dsearch&_sort=3Dd&view=3Dc&_acct=3DC000=
050221&_version=3D1&_urlVersion=3D0&_userid=3D10&md5=3D6f3af550b261236c764ff=
31e532aea4d
During its cruise phase, prior to encountering Jupiter, the Cosmic
Dust Analyser (CDA) onboard the Cassini spacecraft returned time of
flight mass spectra (TOF MS) of two interplanetary dust particles.
Both particles were found to be iron-rich, with possible traces of
hydrogen, carbon, nickel, chromium, manganese, titanium, vanadium and
minor silicates. Carbon, hydrogen, oxygen and potassium are also
present as possible contaminants of the impact target of CDA.
Silicates and magnesium do not feature predominantly in the spectra;
this is surprising considering the expected dominance of silicate-rich
minerals in interplanetary dust particles. The particle masses are
and . The corresponding radii ranges for the particles, assuming
densities from 7874-2500 kg m-3 are 0.7-4 =ECm and 2.6-6.8 =ECm,
respectively. With the same density assumptions the =E2 values (ratio of
radiation pressure to gravitational force) are estimated as 0.027-0.21
and 0.016-0.06 respectively, allowing possible orbits to be
calculated. The resulting orbits are bound and prograde with semi-
major axes, eccentricities and inclinations in the region of 0.3-1.26
AU, 0.4-1.0 and 0-60=B0 for the first particle and 0.8-2.5 AU, 0.2-0.9
and 0-30=B0 for the second. The more probable orbits within these ranges
indicate that the first particle is in an Aten-like orbit, whilst the
second particle is in an Apollo-like orbit, despite both grains having
very similar, predominantly metallic compositions. Other possible
orbital solutions for both particles encompass orbits which more
closely resemble those of Jupiter-family comets.
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although the particle masses given in the link page are small, they
are nevertheless a cause for concern when considering fast (warp?)
spaceships.
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| User: "" |
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| Title: Re: Interplanetary dust detected by the Cassini CDA Chemical Analyser |
17 Jan 2008 07:44:42 PM |
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Both particles were found to be iron-rich
That's interesting. Iron-rich particles without silica were expected
to be in the minority out there. Accounting for less than 1% of all
particles. Perhaps both particles came from the same source.
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