[meteorite-list] Astrophysicists Discover Possible Nanodiamond Formation In The Early Solar System

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:06 2004
Message-ID: <200207121533.IAA15613_at_zagami.jpl.nasa.gov>

http://www.llnl.gov/llnl/06news/NewsReleases/2002/NR-02-07-04.html

Lawrence Livermore National Laboratory

Contact: Anne Stark
Phone:(925) 422-9799
E-mail: stark8_at_llnl.gov

FOR IMMEDIATE RELEASE: July 11, 2002

NR-02-07-04

Astrophysicists Discover Possible Nanodiamond Formation In the
Early Solar System

LIVERMORE, Calif. -- An astrophysicist from Lawrence Livermore
National Laboratory's Institute for Geophysics and Planetary
Physics has found that some nanodiamonds, the most famous and
exotic form of stardust, may instead have formed within the inner
solar system.

The findings argue with the wide held belief that nanodiamonds
recovered from meteorites from the asteroid belt have been the
most abundant type of presolar stardust grain.

IGPP Director John Bradley, in conjunction with scientists from
the Georgia Institute of Technology, the University of Washington,
NASA Goddard Space Flight Center and the Natural History Museum
in London, report their discovery in today's edition of Nature.

"We presumed that if we studied (micro) meteorites (also known
as interplanetary dust particles) from comets further out in our
solar system, we would find more nanodiamonds," Bradley said.
"But we're just not seeing them. One theory is that some,
perhaps most, nanodiamonds formed within the inner solar system
and are not presolar at all."

Interplanetary dust particles are collected in the stratosphere
using NASA ER2 aircraft and they are made up of irregularly
shaped grains of carbon and/or silicates.

One origin of stardust is from supernovae, the cataclysmic
deaths of a star. For more than 30 years, astrophysicists have
looked to stardust, a sort of remnant of stars, to tell the
story of our solar system's origins.

But Bradley and the group of researchers report that at least
some of the oldest cometary interplanetary dust particles
contain little or no nanodiamond stardust at all.

"This raises all sorts of questions about the origins of our
solar system," Bradley said. "Our findings are consistent with
recent research that has detected nanodiamonds within the
accretion discs of other young stars that are similar to our
early solar system."

The group concludes that an alternative explanation for the lack
of nanondiamonds in the early meteorites is that all meteoritic
nanodiamonds are presolar, but that their abundance decreases
the further they are from the sun. In that case, our
understanding of large-scale transport and circulation within
the early solar system is incomplete.

Founded in 1952, Lawrence Livermore National Laboratory is a
national security laboratory, with a mission to ensure national
security and apply science and technology to the important
issues of our time. Lawrence Livermore National Laboratory is
managed by the University of California for the U.S. Department
of Energy's National Nuclear Security Administration.
Received on Fri 12 Jul 2002 11:33:28 AM PDT