(meteorobs) Eta Aquariids 2007

Mikiya Sato mail at kaicho.net
Thu Apr 26 03:51:14 EDT 2007


Dear all,

I am Mikiya. Thak you for all reply.
I answer some questions.

About last Orionids (2006):
I calculated that the other trails which were ejected in -1265,
 -1197 and -910 caused the outburst of Orionids in 2006.
The structures of these trails were also very complex.
The trails were different from this Aquariids, and these
 were older than the trail of Aquariids.
I am contributing the details of Orionids 2006 to a paper.

About old orbital elements of parent comet, 1P/Halley :
I used the orbital elements calculated by Yeomans and Kiang;
 1981, Mon. Not. R. astr. Soc., 197, 633.
The element in -1403 was the oldest in the paper.

About high ejection velocity (-20m/s):
When I calculated, it is as following examples.

Giacobinids 1999 : +60m/s (1959), +69m/s (1966)
Leonids 2006     : +88m/s (1932)
Leonids 1969     : +86m/s (1932)

But these trails were not so old, surely.
In the case of Orionids 2006, the value of ejection velocity
 was about +11m/s and about -10m/s, this absolute values were
 lower than the value of this Aquarids.
(This data may be not so good for Aquarids 2007.)

Best wishes,

Mikiya Sato


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