Flagstaff captured the event good enough to obtain some info. I looked
at the Los Alamos cam and like Mayhill, only flashes. The FACT cam lost
it's interent connection but is still running if someone can get there
and load a flash drive. Payon's computer was down.
Jim
On 4/14/2014 2:50 PM, Bill Cooke wrote:
The information
I found some info on the fall and here is some stats...
vel 667.2 km/s beg 135.8 km end 40.8 km
is from our Fireballs website and is an automatic, obviously incorrect solution to the
event. There are 2 NASA cameras in southern New Mexico - one, at NMSU, collected decent
data on the event, whereas the other one, located in Mayhill, saw only bright flashes
through clouds, very similar to lightning. The automated software did the best it could
to calculate a trajectory, but lightning events are often confused with fireballs, and it
simply "went home to momma". On the plus side, we have been able to filter out
most of the planes :/
If you use the Fireballs website, please look at the videos. If one or more
shows lightning, then you know the trajectory is crap. In general, any meteor
solution with a speed higher than 72-73 km/s should be regarded with much
skepticism.
Most all sky meteor cameras are similar to the Sandia design and use relatively
low resolution low light level cameras like the Watec 902H2. As a result,
meteor trajectory precision is about 100 meters in normal cases, which
translates to an uncertainty in speed of 5-10%. As mentioned by others, this
affects the semimajor axis and eccenticity (size and shape of orbit) the most,
with the orbital angles (inclination, argument of perihelion, and ascending
node) being much better determined, usually to the 1% level. These are low
precision orbits, good for statistical work, but individual examples should be
used with care.
Regards,
Bill Cooke
On Apr 14, 2014, at 2:54 PM, "Matson, Rob D." <[email protected]>
wrote:
Hi Chris/Shawn/All,
There is obviously something squirrely going on in that generated orbit.
For one thing, look at the error bars on the velocity -- they cover all
possible velocities (and as Chris points out, impossible velocities as
well).
I do have a comment about the oft-quoted 72 km/sec value. It is derived
from the orbital velocity of the earth around the sun which averages
29.78 km/sec encountering a retrograde body at just below solar system
escape velocity, which is around 42.1 km/sec at the earth's average
distance from the sun. This gets you to 71.88 km/sec. However, earth's
maximum orbital velocity (which occurs at perihelion in early January
each year) is 30.29 km/sec. And solar system escape velocity at earth's
perihelion distance is 42.48 km/sec. So that increases the closing
velocity to 72.77 km/sec. However, this still isn't the theoretical
maximum closing velocity, since I haven't included the acceleration of
the intercepting body due to earth's gravity well.
At an initial closing speed of 72.77 km/sec, there isn't a lot of time
for the earth's gravity to act on the body before it hits the atmosphere,
so the velocity boost is much smaller than earth's escape velocity (11.2
km/sec). From conservation of energy considerations, it can be shown
that the square of the impact velocity is equal to the sum of the
squares of the escape velocity and the approach velocity. So:
Max impact velocity = SQRT(11.2^2 + 72.77^2) = 73.63 km/sec
So in January, it is certainly possible to have a meteor with a
velocity above 73 km/sec. Anything above 73.63 would require the object
to have either originated outside the Solar System, or (as Chris
mentioned) to have been involved in a slingshot encounter with
another planet prior to encountering earth.
--Rob
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Chris Peterson
Sent: Sunday, April 13, 2014 1:10 PM
To: [email protected]
Subject: Re: [meteorite-list] HUGE Meteor Sighting in Cottonwood AZ - Stats
from fall
There is almost no possibility of a meteor having that speed. The maximum
possible velocity a body in orbit around the Sun can encounter the Earth at is
72 km/s. Anything faster than that would exceed the solar escape velocity,
implying either some sort of slingshot orbit or a body originating outside the
Solar System. Only a few meteors have been observed with velocities above 72
km/s, and those only a bit more, and perhaps of questionable measurement. More
are in radar data (small particles), but it has been called into question if
these actually have the velocities being measured.
Suffice to say, last night's meteor showed the characteristics of a low to
medium speed parent body- something between 11 km/s and say 40 km/s.
What is the source of the data you are using for your calculations?
Chris
*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
On 4/13/2014 1:57 PM, [email protected] wrote:
Hello Listers
I found some info on the fall and here is some stats...
vel 667.2 km/s beg 135.8 km end 40.8 km
Now could a meteorite come from the Vel speed? I mean thats really
fast 667.2km, or that could be a mistake, which I think it is? With
the meteor ending at 40km there is a possibility there could be some
stones on the ground. And after looking at the video I could see the
meteor for around 4 seconds and at the end the meteor got brighter.
more stats below...
Shawn Alan
IMCA 1633
ebay store
http://www.ebay.com/sch/imca1633nyc/m.html
Meteoritefalls.com
time 20140413 3.0738 hours
lat 32 26 22.632 = 32.4396 deg
lon 253 16 38.856 = 253.2775 deg
ht 40.775 b -1.38207 7.62031 -17.37020 -7.68054
alp 300.962 +/- 0.462 deg
del 70.037 +/- 0.310 deg
v_inf 667.240 +/- 977.292 km/s
v_avg 667.240 +/- 977.292 km/s
a -0.002 +/- 0.006 AU
e 493.776 +/- 1444.978
incl 85.761 +/- 3.793 deg
omega 168.225 +/- 0.185 deg
asc_node 22.922 +/- 0.000 deg
v_g 667.102 +/- 977.428 km/s
v_h 668.691 +/- 976.474 km/s
alp_geo 301.065 +/- 0.482 deg
del_geo 70.004 +/- 0.311 deg
q_per 0.982 +/- 0.001 AU
q_aph -0.986 +/- 0.011 AU
lambda 30.964 +/- 1.513 deg
beta 78.151 +/- 0.165 deg
true anom 11.775 +/- 0.165 deg
T_j hyp
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[email protected]
http://pages.suddenlink.net/chondrule/
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