(meteorobs) Ist Light...and it's hot!

[stange]

Hello Chris,

Interesting, the two types of ablation yielding light & heat. I have not 
taken the time to read the collision theory. I suppose it is the raising of 
K & L shell electrons to a higher state of energy, (K shell can total 2) (L 
shell can total 6) since it is primarily Hydrogen(H1 & N7) involved which 
upon return to their lower state emminate energy in the form of heat & light 
for the collision types.

My understanding of the ram-pressure ablation is that there is a thin zone 
between the ram pressure heating zone and the meteoritic material  which is 
of a (much slower velocity), removing the heated (molten) meteoritic 
material layer by layer.similar to a flow of hot gasses streaming around and 
off the frontal area of the meteor during its flight. The inside temperature 
is unknown to me, and I accept (your) cool interior because of the enormous 
velocity of the object and the short period of flight.

Then, jumping ahead a bit,  I suppose after ram-pressure & ablation of the 
larger mass, has made a progressively smaller mass, it would perform a 
transition to a collision phase of light & heat?

Larry
YCS

----- Original Message ----- 
From: "Chris Peterson" <clp at alumni.caltech.edu>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: 2008/07/08 15:47
Subject: Re: (meteorobs) Ist Light...and it's hot!


> Hi Larry-
>
> This fireball is probably large enough that ram pressure is responsible 
> for
> its heating, but that isn't always the case. For a mass smaller than a few
> millimeters (which can still produce a significant fireball), it isn't ram
> pressure that produces heating but collisions with air molecules. This is 
> a
> direct consequence of the small size of the object with respect to the
> rather large mean free path at high altitudes. Below a certain size, an
> object can't maintain a volume of compressed air in front of it.
>
> In any case, there's no "molten mass" here. At any point along the path, 
> the
> average temperature of the mass is barely above what it was before it
> encountered the atmosphere, most likely below freezing.
>
> It's a nice fireball, about what an allsky camera should record once every
> week or two.
>
> Chris
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
> ----- Original Message ----- 
> From: "stange" <stange34 at sbcglobal.net>
> To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
> Sent: Tuesday, July 08, 2008 3:56 PM
> Subject: Re: (meteorobs) Ist Light...and it's hot!
>
>
>> An effect of ram-air pressure heating the surface and interior of a mass
>> however small, in a high velocity approach from outer space into the
>> earths
>> upper atmosphere.
>>
>> A VERY nice first capture shown as a composite image of meteor ablation
>> which is bright enough to be described as a fireball.
>>
>> Wish it had been my capture. -YCS
>
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