Nov. 16, 1999 -
Astrobiologists began their first airborne observation night to study the
Leonid meteors on Nov. 16, as the Earth began to enter the debris train
left by the periodic comet 55P/Tempel-Tuttle.
At 21:50 GMT, on Nov. 16, the ARIA and FISTA, two United States Air Force
planes, departed from Mildenhall in the United Kingdom for Tel Aviv Israel.
During the overnight flight to Israel, the two aircraft flew approximately
80-100 miles apart from each other and as high as 38,000 feet.
The mission flight path took the scientists southwest of Mildenhall, over
Lands End and out of the United Kingdom. The aircraft then turned south to
fly over north central Spain, and then turned east to fly over Barcelona.
The flight continued over Corsica, across the boot of Italy, over central
Greece, and across the Mediterranean into Israel. ARIA and FISTA landed in
Tel Aviv at 04:20 GMT Nov. 17.
The scientists and crew members aboard the FISTA and ARIA had a very
successful first night of their Astrobiology mission. In addition to
observing meteors, the team took measurements of air glow, observed and
recorded lightning over Spain, and saw Jupiter and Saturn clearly in the
night sky. They also successfully demonstrated that live images of the
meteors could be sent from the plane, over the TDRS satellite, to the
Internet.
The science team on the FISTA was thrilled with the collected data. "By
the end of this first mission night we have already exceeded the number of
meteors we observed with our mid-infrared instruments during the entire
1998 mission over Japan," said Peter Jenniskens, Leonid mission chief
scientist.
The mid-infrared spectrographs, contributed by the Aerospace Corporation,
are being used to detect the unique fingerprint of complex organic matter -
like that required for life - in meteors. The instruments are also
expected to provide information on the formation of solid particles and the
heat of the meteors as they enter the atmosphere.
"A total of 10 meteors crossed the field of view of our spectrograph,"
reported George Rossano, a researcher on the FISTA aircraft. "I'm hopeful
that these meteors will result in the first successful mid-infrared
fingerprint of a meteor."
On ARIA, the flux measurement team counted meteors without actually looking
out the window to see them; researchers wore goggles that displayed images
from cameras that were pointed out of the airplane's windows. The number
of Leonid meteors and sporadic meteors counted by each team member was
entered into a laptop computer.
Jane Houston, a member of the flux measurement team and one of several
amateur astronomers on the mission, explained how the team differentiated
between Leonid and sporadic meteors. "The Leonid meteors radiate from the
constellation Leo, while sporadic meteors fall randomly across the sky."
Each of the team members' laptop computers was linked to a central laptop
computer, and near real-time data indicating the total number of meteors
counted was provided. "The methods developed to count meteors for this
mission could revolutionize the way future meteor showers are monitored,"
claimed Kelly Beatty, another amateur astronomer on the flux measurement
team.
At the end of the night, the flux team reported observing approximately 14
sporadic meteors per hour and a Leonid zenith hourly rate of approximately
15 meteors per hour. The zenith hourly rate is the number of meteors an
observer on the ground would see under perfect observing conditions.
"These rates for Leonids are almost twice as high as those we would
normally see the night before the expected peak," explained Dr. Jenneskins,
"I'm optimistic this is an indication that we will see a good storm
tomorrow night."
The peak of the Leonid storm is expected at 02:00 GMT Nov. 18 over Europe
and the Middle East. The international science team studying the Leonids
will be flying from Tel Aviv to Lajes Airbase during the storm peak. It
may be possible to see the Leonid meteor storm in the United States on the
night of Nov. 17 (9:00 p.m. EST). However, best viewing may actually be in
the predawn hours of Nov. 18.
The Leonid Multi-instrument Airborne Campaign is an Astrobiology mission
from NASA Ames Research Center at Moffett Field, CA. The campaign is
jointly funded by the United States Air Force and the National Aeronautics
and Space Administration. Astrobiology is an interdisciplinary field that
studies the origin, evolution, distribution and destiny of life in the
universe.
For current information about the Leonid Multi-instrument Airborne
Campaign, and to watch live Leonid coverage on the Internet, visit:
http://leonid.arc.nasa.gov/
