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Re: (meteorobs) Martian Meteors

Hi,

a group here from the Space Science Department of the European Space Agency
was proposing a small camera to observe meteors from the European Mars
Express orbiter, called MIOS = Meteor and Impact Observations from Space
(which - unfortunately - was not selected for the mission). Myself and
Zdenek Ceplecha from Ondrejov Observatory did some simulations on what to
expect. Here is a table listing mass, magnitude, and terminal height of a
"typical" meteor. We assumed 15 km/s  for the average velocity.

m in kg     max mag         terminal height in km
            at 100 km dist.
0.0001      +4.6            55
0.001       +2.2            48
0.01        -0.1            43
0.1         -2.5            36
1.0         -5.0            30
10.0        -7.6            23
100         -10             15
1000        -12             8
10000       -15             0!

The magnitudes are similar to those produced in Earths atmosphere, only the
meteors appear lower, between 50 and 30 km as supposed to 80 - 120 km in
the Earths atmosphere. The flux of interplanetary particles around Mars is
expected to be a little bit lower than around the Earth, but that's
disputed. Meteor streams would be different - Alexandra Terentjeva did a
study in 1993 which comets intersect Mars' orbit and could generate a stream.

Hitting the ground: In our model, the mass to penetrate the atmosphere is
between 1e3 and 1e4 kg. This assumes a cometary particle - for more compact
particles with densities higher than 1 g/cm3, we would actually have
smaller masses reaching the ground. We concluded that from a Mars orbiter
you could actually see both a meteor and the flash of the impact of the
same meteor. Chances to see an event large enough were about one every 1000
hours if you observe with a camera from an 500 km orbit and your camera has
75 deg field of view. 

At 11:35 PM 11/2/98 +1100, you wrote:
>Has anyone calculated if the Martian atmosphere is thick enough to produce
meteor phenomena
>and if so at what height would we see them at ?
>
>Sure would mean allot more smaller meteorites reaching the surface.
>
>Just something to think about.
>
>Adam Marsh
>Asst Director, ASV Meteor Section.             
>Melbourne, Australia.
>
>
>
>
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Detlef Koschny                      email: dkoschny@estec.esadot nl
European Space Agency
ESTEC Sci/SO
Keplerlaan 1                              phone: +31-71-565-4828
NL-2201 AZ Noordwijk ZH                     fax: +31-71-565-4697
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