(meteorobs) Meteorobs day and night time meteors

[Chris Peterson]

I'd say that for all practical purposes, there's no difference between a 
daytime and nighttime meteor of any given magnitude. Very little of the 
meteor's light comes from gas emission lines. The light is simply the 
blackbody emission of a hot object, and the meteor temperature is the same 
day or night.

There might be a slight difference in the trail characteristics due to the 
phenomenon you describe. But how would you tell? Any ionized gas emission in 
the trail is going to be invisible in the day, regardless of the meteor 
magnitude. I don't think you can ever see any component of a meteor trail in 
the day except for smoke and dust.

Of course, when you talk about "brilliance" the question gets tricky, since 
you are now bringing in issues of perception. There's no doubt that a -6 
magnitude meteor seen at night will be perceived as much brighter than a -6 
magnitude meteor seen in the day, even though a camera would easily show 
that they have the same intensity.

Chris

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


----- Original Message ----- 
From: "drobnock" <drobnock at penn.com>
To: <meteorobs at meteorobs.org>
Sent: Saturday, July 19, 2008 7:49 AM
Subject: (meteorobs) Meteorobs day and night time meteors


> Question for the group.
>
> If it were possible to see a - 6 magnitude fireball with the same
> brilliance in the day time as at night,  would the same amount of energy
> be needed to ionize the gas around a meteor to be a visual -6
> meteor?     Consider that the same fireball in question is viewed both
> in the day and  at night. The meteor being viewed  is of the same
> composition, speed entering the atmosphere, trajectory, and  mass. The
> same fire ball in all factors.
>
> There is  event  known as the "dark effect"  that occurs with certain
> inert gasses - neon being one of them is electrically excited. It is
> known that a neon glow tube requires less energy to excite the gas in
> the tube if the tube is exposed to sun light as being started in the
> dark.
>
> Other gases may have similar characteristics.
>
> Consider for the question that most of our atmosphere is made up of
> nitrogen(78% by volume) and  oxygen (21% by volume). The remaining 1% of
> the atmospheric gases are known as trace gases because they are present
> in such small concentrations.  This question is considering that the
> most abundant  trace gases are argon (approximately 1% by volume).
> Others include  neon, helium, krypton and xenon may exhibit the "dark
> effect" when ionized.
>
> Those observing meteors by radar, is there a  quantitative difference in
> the density of the trail for night and day time meteors?
>
> Thanks for any comments.
>
> George John Drobnock