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

[Ron Baalke]

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