[meteorite-list] ON POSSIBLE SOLAR ORIGIN OF METEORITIC NANODIAMONDS

From: Shawn Alan <photophlow_at_meteoritecentral.com>
Date: Fri, 14 May 2010 22:26:13 -0700 (PDT)
Message-ID: <420793.50256.qm_at_web113607.mail.gq1.yahoo.com>

Hello Listers,

The next few days ill be posting articles that pertain to the?topic of nanodiamonds.
?
First up:
?
ON POSSIBLE SOLAR ORIGIN OF METEORITIC NANODIAMONDS

Galina K. Ustinova ,Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow V-334, 119991 Russia; E-mail: ustinova at dubna.net.ru
?
The laboratory experiments on synthesis of artificial nanodiamonds demonstrate an extremely large spectrum of the physical and chemical conditions for realization of this process. Indeed, the synthetic nanodiamonds are obtained in the processes of detonation synthesis at high pressure and temperature, as well as by low-pressure condensation being similar to chemical vapor deposition at moderate temperatures (CVD-techniques), and as well as by irradiation of carbonaceous materials with laser, intensive ultraviolet radiation or high-energy particles [1]. In view of the variety of the admissible astrophysical conditions, one may anticipate ubiquitous distributions of nanodiamonds in cosmos. Thus, the observations of the interstellar extinction testify to the fact that up to 10% of the interstellar carbon could be bound up in the interstellar diamond [2]. Nanodiamonds with the lognormal size distribution being similar to that for meteoritic ones are observed
 in circumstellar disks in the systems of Herbig emission stars of HD97048 and Elias 1 [3], in the carbon-enriched protoplanetary nebulae [4] an
n in the interplanetary dust [5]......

Of course, it cannot be excluded that, somewhere at the periphery of the collapsing protosolar nebula, some presolar grains of other generation could sur-vive and even preserve the noble gases of their astro-physical sources. According to the estimates of [12], the relative abundance in chondrites of presolar nanodiamonds generated in the atmospheres of AGB stars amounts to ~1% only, and that
d at SNII explosions is < 0.1%.

http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1050.pdf

Shawn Alan
eBayshop
http://shop.ebay.com/photophlow/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340
Received on Sat 15 May 2010 01:26:13 AM PDT