(meteorobs) Cloudbait. A difficult question to ask.

[Francisco Ocaña]

I agree with Chris. There is no clear relationship between sporadic 
fireballs and shower activity and I think the Sun particles are not 
enough to give the extra energy needed to achieve 400km/s (even 1-2 km/s 
more).

However some leonids with extremely short semimajor axis have been 
observed. The possible reason: zodiacal dust hits (Paper by 
Trigo-Rodriguez et al :  
http://www.journals.uchicago.edu/doi/abs/10.1086/427624 ).

My 2 cents!

Paco Ocaña

Chris Peterson escribió:

>No, I don't see any relationship between sporadic fireballs and shower 
>activity.
>
>You need to consider that shower debris is orbiting the Sun. The 
>velocity of a body orbiting the Sun is determined by the mass of the 
>Sun, the distance of the body from the Sun, and the semimajor axis of 
>the orbit. For a circular orbit at 1 AU, the orbital velocity is 29.8 
>km/s. That's how fast the Earth is going. Orbital debris is almost 
>always (probably always) in a fairly eccentric orbit where the semimajor 
>axis will be greater than 1 AU, so when this debris crosses the Earth's 
>orbit, it will be going faster than 29.8 km/s. All of the debris is in 
>the same orbit, so except for tiny variations with respect to the 
>orbital speed, nothing is going slower or faster. That's why there isn't 
>much variation in entry speed for the members of any given shower. What 
>variation there is comes from fairly minor effects such as the additive 
>(or subtractive) component of Earth's rotation (under 1.5 km/s). Since 
>the debris is co-orbital, collisions in the stream aren't going to 
>substantially slow down or speed up any bodies.
>
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