Stardust

Panels of siUca aerogels have already been flown on several Space Shuttle missions (74). Currently a STARDUST mission has been planned by NASA to use aerogels to capture cometary samples (>1000 particles of >15 micron diameter) and interstellar dust particles... 

Example 7.4-5. Dimensioning of equipment for Stardust Chemical Co. plant (after Flatz, 1980)... 

Stardust Chemical Co. planned a new plant for two intermediates. The chemical production processes were not yet fully worked out because of lack of data on how large the production plant would have to be. The following information is not complete and partly misleading. 

Muller H, Wieschaus E 1996 armadillo, bazooka, and stardust are critical for early stages in formation of the zonula adherens and maintenance of the polarized blastoderm epithelium in Drosophila. J Cell Biol 134 149-163... 

Stardust February 7, 1999, saw the start of NASA s Stardust mission the cometary probe, the first mission to collect cosmic dust and return the sample to Earth, has a time-of-flight mass spectrometer (CIDA, Cometary and Interstellar Dust Analyser) on board. This analyses the ions which are formed when cosmic dust particles hit the instrument s surface. In June 2004, the probe reached its goal, the comet 8 IPAVild 2, getting as close as 236 km The CIDA instrument, which was developed at the Max Planck Institute for Extraterrestrial Physics in Garching (near Munich), studied both cometary dust and interstellar star dust. 

Isotopic variations are large enough to exceed terrestrial variations by more than about an order of magnitude. As an example, this is the case for ion probe work on the CNO isotopes of circumstellar grains (see Section Presolar stardust grains... ). These effects can be attributed unambiguously to nucleosynthetic reactions. 

Presolar stardust grains diamond, graphite, carbides and oxides... 

Presolar stardust discovered to date in meteorites constitute no more than 0.5%o of the total mass of the samples, and one common chemical property is that they are acid resistant. Isotopic heterogeneity could also be present in less refractory phases like silicates, provided parent body metamorphism did not erase the differences. Noble gases are not discussed here because they are depleted by many orders of magnitude relative to the Sun and can be dominated by trace exotic minerals. Nitrogen is not discussed for the same reason. The... 

Nittler LR (2003) Presolar stardust in meteorites recent advances and scientific frontiers. Earth Planet Sci Lett... 

Is it perhaps because revolution has failed on Earth that humankind has set out to find evolution in the sky Since that moment of revelation, we have been proclaiming that we are stardust, which is only partly true, because hydrogen is the ash of the Big Bang. Anyway, the cosmos is evolving. We are living in the golden age of evolutionary astrophysics. 

Some street names for cocaine include blow, C, Charlie, coke, crack, dynamite, happy dust, nose candy, rock, snow, snuff, stardust, toot, and white lady. The combination of cocaine and heroin is termed speedball. 

There are two types of presolar grains. Circumstellar condensates condensed from hot gas ejected from dying stars in the immediate vicinity of their parent stars. They are also sometimes called stardust. Circumstellar condensates give snapshots of the life histories of the stars from which they formed. Although the stars themselves no longer exist, the... 

As noted previously, most of the presolar grains so far identified are circumstellar condensates (stardust), but some grains formed in interstellar space. The interstellar grains are not likely to contain large isotopic anomalies. So how can we recognize these interstellar grains in meteorites ... 

Nagashima, K., Krot, A. N. and Yurimoto, H. (2004) Stardust silicates from primitive meteorites. Nature, 428, 921-924. 

Nguyen, A. N. and Zinner, E. (2004) Discovery of ancient silicate stardust in a meteorite. Science, 303, 1496-1499. 

Nittler, L. R. and Cowsik, R. (1997) Galactic age estimates from -rich stardust in meteorites. Physical Review Letters, 78, 175—178. 

The densities of comets Halley and Tempel 2 were estimated to be 0.3 g cm 3, consistent with highly porous objects. However, comet 81 P/Wild2, imaged by the Stardust spacecraft in 2004, appears to be a more coherent object, implying that it has a higher density, -0.6 gcm 3. 

Images of comet nuclei taken during various spacecraft encounters illustrate both similarities and differences. Figure 12.2 compares images of comets Borrelly (taken by Deep Space 1 in 2001), Wild2 (taken by Stardust in 2004), and Tempel 1 (taken by Deep Impact in... 

Oxygen isotopic compositions (relative to standard mean ocean water, SMOW) of several mineral grains in three Stardust particles, each grain denoted by a separate symbol. Open circles are from a CAI comet particle. After McKeegan et al. (2006). 

Mean compositions of tracks and crater residues produced by Stardust particles, compared to Cl chondrite ratios (horizontal lines), (a) Fe- and Cl chondrite-normalized composition determined by averaging 23 track analyses by SXRM (filled squares), (b) Si- and Cl- chondrite-normalized composition of seven crater residue analyses by SEM-EDX (filled squares), and TOF-SIMS analyses for five craters (open squares). Modified from Flynn et al. (2006). 

Measured D/H ratios in five bulk Stardust particles (black dots sizes represent relative particle sizes), and in micron-size subareas in one particle (open circles enclosed by oval) measured by ion microprobe. The particle compositions overlap D/H ratios in comets, IDPs, and the insoluble organic matter in chondrites. Modified from McKeegan et al. (2006). 

In 2004, the NASA Stardust spacecraft passed through the dust cloud surrounding the nucleus of comet Wild2 and captured more than 10 000 particles ranging from 1 to 300 pm in size (Brownlee et al., 2006). These particles were returned to Earth for study in terrestrial laboratories in 2006. Initial results are described in the December 15, 2006, issue of Science. 

Brownlee, D. and 181 coauthors ( ) (2006) Comet 81 P/Wild2 under a microscope. Science 314, 1711-1716. This fascinating article, plus the more focused articles that follow it in the same issue, provide the first characterization of comet dust samples collected and returned by the Stardust spacecraft. 

Flynn, G. J. plus 79 coauthors (2006) Elemental compositions of comet 81P/Wild2 samples collected by Stardust. Science, 314, 1731-1735. 

McKeegan, K. D. plus 45 coauthors (2006) Isotopic compositions of cometary matter returned by Stardust. Science, 314, 1724-1728. 

Sandford, S. A. plus 54 coauthors (2006) Organics captured from comet 81P/Wild2 by the Stardust spacecraft. Science, 314, 1720-1724. 

Tsou, P. plus 19 coauthors (2004) Stardust encounters comet 81P/Wind 2. Journal of Geophysical Research, 109, E12S01, doi 10.1029/2004JE002317. 

The has found wide use in studying presolar grains, IDPs, and Stardust samples, and in analyzing the fine-grained alteration minerals in carbonaceous chondrites. 

Several analytical techniques are based on X-rays emitted from high-energy synchrotron electrons. These have been used to study IDPs and are an important part of the analytical arsenal being used on the Stardust samples. Three of these are discussed here. 

Micro-XRF uses a monochromatic X-ray beam focused to a few microns in diameter. The principle is the same as for the XRF system discussed earlier. A typical analytical mode is to raster the sample under the X-ray beam to produce element maps of the samples. This technique is used to determine bulk compositions of IDPs and the material in the Stardust tracks. 

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