(meteorobs) Meteor picture from Mars?

Bruce McCurdy bmccurdy at telusplanet.net
Mon Jun 6 19:04:20 EDT 2005


    GeoZay wrote:

>>The shooting star  was low in the sky and ran across the horizon, creating
>> a relatively long  spectacle. If you were on Mars and held a fist at 
>> arm's
>> length, resting it on  the horizon, the meteor would have soared barely 
>> above
>> your fist. In  astronomers' terms, it was 14.2 degrees off the horizon.
>> If you could trace the  meteor back and below the horizon, it would have
>> appeared to emanate from the  constellation Cepheus, and so the 
>> scientists have
>> dubbed the apparent meteor  shower the Cepheids.<<
*****

> So one meteor has been seen over mars and we already got a shower name for
> it. I wonder how many degrees below the horizon the "radiant" was? Has a 
> ZHR
> been determined yet? Has a sporadic been considered? I suppose like earth, 
> mars
> would probably have some kind of shower activity almost every night of the
> year...as well as sporadics.
*****

    The wording of the quoted section "If you could trace the meteor back 
and **below the horizon** " is surely in error and should be disregarded. 
Reporter probably doesn't understand the concept of the radiant. The actual 
image of the meteor 
http://www.obspm.fr/actual/nouvelle/jun05/meteor.en.shtml
shows a virtually horizontal path, suggesting the radiant is low (maybe ~ 
10°?) but certainly above the horizon. As surely it must be; just because 
it's Mars doesn't mean the laws of physics have been repealed. The meteor's 
path is apparently consistent with the orbit of Comet Wiseman-Skiff, 
although we are obviously dealing with an extreme example of small number 
statistics. Doesn't get much more extreme than one example. I think it's 
cool they're even trying to make the association.

    Last week I posted a note to the list "amastro" about this meteor, in 
part to congratulate the co-discoverer of its parent comet, Brian Skiff. 
Brian described the discovery and added these comments which may be of 
interest to meteorobs:

*****
    Since Bruce M is interested in this sort of thing, I'll note that
the comet was significantly perturbed by Jupiter in 1984, which upped the
eccentricity and reduced the perihelion distance to about half what it
had been previously---which made it brighter and easier to discover!
The implication thus is that the Martian Cepheid meteor shower now 
associated
with the comet is a recent start-up.  If you visit the JPL orbit page
for the comet:

http://neo.jpl.nasa.gov/cgi-bin/db_shm?sstr=114P

...you can see that the orbit-intersection distance is no more than the
width of the lines used to show the path of Mars and the comet (something I
hadn't known before this morning).  The non-trivial encounters with Jupiter
are still there, too, which I assume dominates things (the comet is in a
typical 3:2 Jupiter resonance now), but clearly further perturbations are
likely over the long term.
*****

    So this year's scoreline on Mars is Meteorites 1, Meteors 1. Two of the 
best astronomy stories of the year.

    Bruce 




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