[meteorite-list] NASA, Partners Reveal California Meteorite's Rough and Tumble Journey (Novato Meteorite)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 15 Aug 2014 19:36:41 -0700 (PDT)
Message-ID: <201408160236.s7G2agSN005404_at_zagami.jpl.nasa.gov>

http://www.nasa.gov/content/nasa-partners-reveal-california-meteorites-rough-and-tumble-journey/

NASA, Partners Reveal California Meteorite's Rough and Tumble Journey
August 15, 2014

[Image]
End of flight fragmentation of the Nov. 18, 2012, fireball over the San
Francisco Bay Area (shown in a horizontally mirrored image to depict the
time series from left to right). These photographs were taken from a distance
of about 65 km.
Image Credit: Robert P. Moreno Jr., Jim Albers and Peter Jenniskens

A meteorite that fell onto the roof of a house in Novato, California,
on Oct. 17, 2012, has revealed a detailed picture of its origin and tumultuous
journey through space and Earth's atmosphere. An international consortium
of fifty researchers studied the fallen meteorite and published their
findings in the August issue of the journal Meteoritics and Planetary
Science.

"Our investigation has revealed a long history that dates to when the
moon formed from the Earth after a giant impact," says Peter Jenniskens,
a meteor astronomer and consortium study lead working for the SETI Institute,
Mountain View, California at NASA's Ames Research Center in Moffett Field,
California.

Jenniskens captured the meteorite's fall in NASA's Cameras for Allsky
Meteor Surveillance and quickly calculated the likely fall area over the
city of Novato. Novato residents Lisa Webber and Glenn Rivera then remembered
hearing something hit their garage roof that night, found the first meteorite,
and made it available for study. Often researchers use the location a
meteorite was found to name to the rock; this meteorite now is officially
known as "Novato" according to the Meteoritical Society.

"We determined that the meteorite likely got its black appearance from
massive impact shocks causing a collisional resetting event 4.472 billion
years ago, roughly 64-126 million years after the formation of the solar
system," says Qing-zhu Yin, professor in the Department of Earth and Planetary
Sciences at the University of California (UC), Davis. "We now suspect
that the moon-forming impact may have scattered debris all over the inner
solar system and hit the parent body of the Novato meteorite."

Yin and collaborators also measured when the meteorites' parent body broke
into fragments during another massive collision, about 470 million years
ago. This created a debris field in the asteroid belt between Mars and
Jupiter from which Novato-like meteorites, which are known as "L6 ordinary
chondrites," now are coming to Earth.

Scientists had earlier identified the similarly-aged Gefion asteroid family
in the middle of the main asteroid belt as the likely source of Novato-like
meteorites. Jenniskens successfully measured the Novato approach orbit
and confirmed that Gefion can be the source of these meteorites.

"Novato broke from one of the Gefion family asteroids nine million years
ago," said Kees Welten, cosmochemist at UC Berkeley. "But may have been
buried in a larger object until about one million years ago," added Kunihiko
Nishiizumi, cosmochemist also of UC Berkeley.

After the Novato meteoroid was ejected from the asteroid belt, its path
periodically brought it back to the asteroid belt. Scientists at Ames
measured the meteorites' thermoluminescence ??? the light re-emitted when
heating of the material and releasing the stored energy of past electromagnetic
and ionizing radiation exposure ??? to determine that Novato may have
had another collision less than 100,000 years ago.

"We can tell the rock was heated, but the cause of the heating is unclear,"
said Derek Sears, a meteoriticist working for the Bay Area Environmental
Research Institute in Sonoma, California, at Ames. "It seems that Novato
was hit again."

When the Novato meteoroid finally hit Earth's atmosphere, scientists approximate
it measured 14 inches (35 centimeters) and weighed 176 pounds (80 kilograms).
Robert P. Moreno, Jr., photographed in great detail the meteoroid's final
breakup in Earth's atmosphere from Santa Rosa, California.

"These photographs show that this meteorite - now one of the best studied
meteorites of its kind - broke in spurts, each time creating a flash
of light as it entered Earth's atmosphere," said Jenniskens. "In all,
six surviving fragments were recovered."

Researchers were surprised to find that all these impacts did not completely
destroy the organic compounds in this meteorite. Qinghao Wu and Richard
Zare of Stanford University in California measured a rich array of polycyclic
aromatic hydrocarbon compounds - complex, carbon-rich molecules that are
both widespread and abundant throughout the universe.

Daniel Glavin at NASA's Goddard Space Flight Center in Greenbelt, Maryland,
led a team to search the Novato meteorites for amino acids ??? molecules
present in and essential for life on Earth ??? and detected some unusual
non-protein amino acids that are now very rare on Earth but indigenous
to the Novato meteorite.

"The quick recovery of the Novato meteorites made these studies possible,"
says Jenniskens.

The research was supported by the NASA Near Earth Object Observation,
Planetary Astronomy and Cosmochemistry programs, and the Swiss National
Science Foundation.

For more information about the Cameras for Allsky Meteor Surveillance
project and Novato meteorite, visit: http://cams.seti.org/index-N.html

 

Text issued as Ames news release 14-057AR

Rachel Hoover
Ames Research Center, Moffett Field, Calif.
650-604-4789
rachel.hoover at nasa.gov

Seth Shostak
SETI Institute, Mountain View, Calif.
650-960-4530
sshostak at seti.org
Received on Fri 15 Aug 2014 10:36:41 PM PDT