[meteorite-list] Fireball report from this morning in Utah

[Chris Peterson]

Ed-

Reentering objects are responsible for only a tiny fraction of 
fireballs- well under 1% based on my empirical data. I think Marco has 
looked at this, too... he might have better numbers. In any case, while 
you certainly might have seen space junk, natural meteors are much more 
likely.

There seems to be a strong correlation between color and speed, with 
slow objects being seen as bright green, and faster objects seen as pale 
green or white. I expect that is simply because the faster objects are 
hotter, and the "white" blackbody output is swamping the fainter oxygen 
emission. Reentering space junk is slow, and is usually reported as 
green.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "E.P. Grondine" <epgrondine at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Thursday, December 07, 2006 9:00 AM
Subject: Re: [meteorite-list] Fireball report from this morning in Utah


> HI Chris -
> --- Chris Peterson <clp at alumni.caltech.edu> wrote:
>
>> most of the rest see some variation of
>> green, ranging from pale lime to bluish. This is
>> probably caused by the 558 nm "forbidden"
>> oxygen emission line, mixed to varying degrees with
>> a white thermal emission.
>
> What is this? I remember that the first of the two
> fireballs which I have seen was so green I thought it
> was a re-entering war-head.
>
> Ed