[meteorite-list] Fireball temperatures

From: Shawn Alan <photophlow_at_meteoritecentral.com>
Date: Fri, 14 May 2010 11:02:45 -0700 (PDT)
Message-ID: <604214.58363.qm_at_web113613.mail.gq1.yahoo.com>

Hello?Listers,
?
Here is the article to Jiri Borovicka fireball temp analysis called A fireball spectrum analysis
?
Abstract:

A grating spectrum (45 A/mm) of a fireball of -9th absolute magnitude and velocity of 18 km/s has been analyzed. A new simple model for meteor spectra has been developed. Thermal equilibrium is assumed and self-absorption is taken into account. The free parameters of the model are the temperature, the column density of Fe I atoms, the relative abundances of other atoms, and the visible surface area of meteor radiating volume. The synthetic spectrum based on this model was computed and compared with the observed spectrum. The values of the free parameters were calculated by the least squares method. Then the abundances of neutral atoms were corrected for ionization to obtain the true ratios of chemical elements. The abundances of Fe, Na, Mg, Ca, Ti, Cr, Mn, Ni, and Al were determined such way. The computations were performed independently at 43 points along the fireball trajectory between heights of 57-35 km. It was found that thermal equilibrium was
 relatively well satisfied at the heights below 50 km. The temperature varied on the range 3500-4700 K. But there is also a spectral component with temperature of about 10,000 K in the spectrum. This component consists of a few lines of Mg II, Si II and Fe II and originates probably in the shock wave. The chemical composition of the radiating gas varied along the fireball path and does not reflect the chemical composition of the meteoroid itself. The refractory elements (Al, Ca, Ti) are underabundant in the gas. The material was ablated by melting in liquid phase and then evaporated in surrounding hot gas, but the refractory (low melting) elements were evaporated incompletely or too late. About 95% of the hot gas around the meteoroid were formed by the air.
?

http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1993A%26A...279..627B&db_key=AST&page_ind=0&data_type=GIF&type=SCREEN_VIEW&classic=YES&high=4bb95d172c09137?
?
?
Shawn Alan
eBaystore
http://shop.ebay.com/photophlow/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340

?
?
[meteorite-list] Fireball temperaturesEd Majden epmajden at shaw.ca
Fri May 14 12:49:19 EDT 2010


Previous message: [meteorite-list] Fireball Temperature?
Next message: [meteorite-list] off topic beads of charity
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

See: http://folk.ntnu.no/ltheen/meteor/meteor_physical.html

Do a search with "google" "for meteor fireball temperatures".
There are several papers related to this topic.

>From a spectroscopic point of view, Jiri Borovicka suggests that the
temperature of the main component is around 4500 K and the second
component is around 10,000 K (Borovicka 1994) Planetary Space Sci,
42, 145-150.

Ed Majden - AMS Meteor Spectroscopy
Courtenay, B.C. Canada.





Previous message: [meteorite-list] Fireball Temperature?
Next message: [meteorite-list] off topic beads of charity
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

More information about the Meteorite-list mailing list
Received on Fri 14 May 2010 02:02:45 PM PDT