[meteorite-list] Meteorite Discovery Supports Theory on Supernova Role in Solar System Creation

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon Jan 24 18:02:03 2005
Message-ID: <200501242301.PAA13247_at_zagami.jpl.nasa.gov>

http://www.eurekalert.org/pub_releases/2005-01/asu-mds012405.php

Public release date: 24-Jan-2005

Contact: James Hathaway
hathaway_at_asu.edu
480-965-6375
Arizona State University

Meteorite discovery supports theory on supernova role in solar system
creation

Clear evidence in a Chinese meteorite for the past presence of
chlorine-36, a short-lived radioactive isotope, lends further support to
the controversial concept that a nearby supernova blast was involved in
the formation of our solar system, according to a report forthcoming in
the February 1 issue of the Proceedings of the National Academy of
Sciences (to be published online today).

Known as the Ningqiang carbonaceous chondrite, the primitive meteorite
is a space relic that formed shortly after the solar system's creation.
It contains pockets of still older materials or "inclusions" that
contain that contain calcium, aluminum and sodalite, a chlorine-rich
mineral.

A Chinese-American team of scientists including Yangting Lin, Ziyuan
Ouyang and Daode Wang from the Chinese Academy of Sciences, and Yunbin
Guan and Laurie Leshin from Arizona State University found the rare
isotope sulfur-36 in association with the sodalite. Though it can be
formed in various ways, sulfur-36 is a natural decay product of
chlorine-36 and its association with the chlorine in the sodalite is
thus strong evidence for the past presence of chlorine-36, which has a
half-life of only 300,000 years, in the early solar system.

The solar system's chlorine-36 could have formed in two different ways -
either in the explosion of a supernova or in the irradiation of a
nebular cloud near the forming Sun. The irradiation explanation is
unlikely in this case, however, since the mineral the chlorine-36 was
discovered in must have formed a significant distance from the sun.

"There is no ancient live chlorine-36 in the solar system now," said
Leshin, who is director of ASU's Center for Meteorite Studies. "But this
is direct evidence that it was here in the early solar system.

"We have now discovered the first solid evidence for two different
short-lived radionuclides in the GeoSIMS Lab at ASU - iron-60 and
chlorine-36 -- and both of them provide strong evidence for where the
solar system's short-lived radionuclides came from. It's producing a
really strong argument that these radionuclides were produced in a
supernova that exploded near the forming solar system and seeded the
solar system with these isotopes."

In a "Perspectives" article in the journal Science last spring, Leshin
and others argued that the presence of iron-60 was evidence that the
solar system formed as a result of violent star-creation processes in a
dense nebula rife with short-lived, high-mass stars and supernovas - a
very different creation story than the traditional view that the solar
system formed from a slowly condensing molecular cloud. (To see the
release on the Science paper, see
http://www.asu.edu/asunews/research/sun_earth_creation.htm )

Leshin points out that the current paper is part of a growing
collaboration between space sciences at ASU and the Chinese science
community, in this case being driven by Guan, a native of China, and
manager of the ASU GeoSIMS Lab.

"Lin, the first author on this paper, was a visiting fellow in our lab
for six months. We've published several papers on meteorites with groups
in China - it's a very fruitful relationship," she said.

###

Source: Laurie Leshin, 480-965-0796, laurie.leshin_at_asu.edu

Related images: http://clas.asu.edu/newsevents/pressreleases/photos/HII/
Received on Mon 24 Jan 2005 06:01:52 PM PST