(meteorobs) Re^2:2012 Draconids

Mikhail Maslov ast0 at mail.ru
Thu Jan 27 09:24:56 EST 2005


Hello,

Some words about fM. It shows how much the trails are strethed
alongside themselves, i.e., how many particles the trail contailns per
unit of length. So the suggested activity is in direct proportion to
fM value. It depends mostly on the difference between times of
consequent nodal passages made by trail particles. Also some influence
have changes in (rd-re) measure as well as in solar longitudes, but
it is usually very small. To compute fM I use the same mechanism as
for Leonids. In Leonids case my fMs are in good accordance with
results of other researchers. But what happened in Draconids case?
Mikia, maybe you also considered differences in relative velocities
between Leonids and Draconids. My fM is arond 15 times greater, than
yours and it is similar to ratio Leonids relative velocity/Draconids
relative velocity (note: I mean velocity in space, not of atmosphere
entry).

Best regards, Mikhail Maslov


MS> I am Mikiya Sato.

>>Now I've computed the circumstances. Unfortunately, the hole in 1959
>>trail tells that the most probable is virtual absence of activity. But
>>I think there is sence to check 2006 year - younger trails could make
>>some intersections.
>>
>>
>>Trail rd-re.  ej. Vel.  fM     sol.long  max. Time   ZHR ex.
>>       AU       m/s              deg        UT
>>1959 +0,00121  38,7    0,051*  195,624  08.10.12 16:41  0**
>>* - very low for Draconids
>>** - computed as if it was 55P, not 21P.

MS> I also calculated in 2012. And I had a similar result about 
MS> the trail of 1959 and a interesting result about trail of 1966.
MS> My results are as follows;

MS> In 2012:
MS> Trail   DateTime(UT)  SolLong   dR(AU)  D.sp.  fM      Comment
MS> 1959    Oct.08 16:39  195.624  +0.0012  +38.5  0.0033  FM is very small.
MS> 1966-1  Oct.08 16:47  195.630  +0.0042  +43.1  0.25    Distance is far.
MS> 1966-2  Oct.08 17:27  195.657  +0.0004  +51.4  ****    *1

MS> A fM value of 1959 is very small because of perturbation by the Earth
MS>  in 1992. (My value is smaller than the value by Mikhail Maslov.)

MS> The main trail of 1966(1966-1) is far from the Earth orbit,
MS>  about 0.004[AU]. But a part of trail of 1966(1966-2) is very near.
MS> This part has bent because of perturbation by the Earth in 1972 and 1992.
MS> It seems to encounter the earth in the curved top of trail. 
MS> This is very interesting.

MS> And, I show the results in 1999, referring.
MS> In 1999:

MS> In 1999:
MS> Trail   DateTime(UT)  SolLong   dR(AU)  D.sp.  fM      Comment
MS> 1959    Oct.09 10:50  195.714  -0.0026  +60.0  0.20    *2
MS> 1966    Oct.09 11:59  195.761  -0.0014  +69.4  0.26    *2

MS> In Japan, the actual peak in 1999 was observed around 11:00(UT) on 
MS> October 9, the HR was about 20 to 30. (*2)
MS> (http://kaicho.pobox.ne.jp/tenshow/meteor/21p/1998e.htm)
MS> Discharge speed were very large (about 60 and 69 [m/s]), 
MS> but I think that this peak was brought by these trails.
MS> (Perihelion distance of these two revolutions, was nearer than 
MS> others.)
MS> So, small or middle peak may be observed in 2012 however discharge 
MS> speed of trail in 2012 is so large.

MS> Best wishes,
MS> Mikiya Sato
MS> ---
MS> Mailing list meteorobs
MS> meteorobs at meteorobs.org
MS> http://lists.meteorobs.org/mailman/listinfo/meteorobs




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