[Prev][Next][Index][Thread]
Re: (meteorobs) 'Glowworms In Sky' Studied At Starfire Optical Range
Hello Lew, et al,
Below is a copy of the abstract submitted to the Asteroids, Comets, Meteors
conference held at Cornell University, in Ithaca, NY, this summer (1999),
concerning the work about which the "glow worm" article was written. The
abstract might be a bit more informative than a journalist's story. I
attended this presentation, which was given during the Leonids session held
on Tuesday, July 27, and hosted by Peter Jenniskens.
------ [from ACM 1999 Abstract Listings]
07.07-Invited
Leonid Trails and Lasers -- A Video
Jack Drummond (USAF), Mike Kelley (Cornell University), Chet Gardner
(University of Illinois)
During the 1998 Leonid meteor shower, the University of Illinois'
sodium lidar was used at the Starfire Optical Range on Kirtland AFB, NM,
to measure the impact of the passage of a meteor on the number density,
temperature, and velocity of sodium atoms at 100km altitude. A 200W copper
vapor laser (CVL) was also used in an attempt to measure back-scatter from
particulates in the contrails of the Leonids. Guided by a human observer,
the Starfire's 3.5m telescope, used as a receiver for the lidar, was
steered onto the lingering trails of meteors and a 5 degree wide Xybion
camera, attached to the headring of the telescope, recorded the scene. A
15 minute highlight video will be presented showing the evolution of the
lingering trails as well as the lidar and the CVL probing them.
Almost all of the meteors that produced lingering trails greatly
enhanced the naturally occurring sodium layer at 100km. The lingering
trails generally appeared as evanescent smoke rings that evolved rather
quickly, with the path of the meteor marked by a double walled, optically
thin tube. One meteor, however, was radically different. The brightest
meteor of the night (about -4.5 magnitude) produced NO sodium enhancement.
Its contrail appeared optically thick, turbid, had right angles over its
path, lingered the longest, more than 30 min, and simply dissipated,
rather than evolved. These trails, and their evolution, will be featured
in the video.
--------[end]
Take care,
Jim
James Richardson
Tallahassee, Florida
richardson@digitalexp.com
Operations Manager / Radiometeor Project Coordinator
American Meteor Society (AMS)
http://www.amsmeteors.org
To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html
References: