[Prev][Next][Index][Thread]

Re: (meteorobs) Fwd: How fast do Meteors go?




Robert, your interpretation makes a lot of sense. But it assumes that Marco
didn't define his terms correctly. Marco's original post says:

>log M(m)=2.98-0.44m-3.89log V[inf]-0.67log(sin h)
>
>in which m=magnitude, M=mass in kg, V[inf] is speed (infinite, not
>geocentric) and h is the zenith distance of the radiant.

In other words, Marco defines M as meteoroid mass, not meteor magnitude.

Now in your interpretation, we would then assume M(m) means "mass as a
function of magnitude", so that the magnitude could be derived as a log
of some god-awful power of 10 (based on Vinf and h) divided by the mass!

   0.4 m = log [ exp(2.98-3.89logVinf-0.67log(sin h)) / M ]

Lordy... Does that make any sense? It may: but aren't there any second-
order terms in this magnitude function then?? Shoot, I'm going straight
home tonight to check through my copies of Oepik and D.W.R. McKinley! :)



As for that funky "Vinf" term, Robert, it was discussed last Summer: it
is the atmospheric entry velocity of the meteor, which takes into account
not only the meteoroid's orbital velocity relative to Earth (which seems
to be called 'Vgeo'), but also the Earth's gravitational attraction on the
meteoroid, and Earth's rotational velocity - and maybe other things, too?

Clear skies,
Lew Gramer


To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html

Follow-Ups: References: