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(meteorobs) Re: Call for Observations for delta Cancrids

Hi Huang,

It would occur to me that both the geocentric velocity of the theoretical
stream of your asteroid is clearly too high, and the date of maximum too
early, to make a viable association with the delta Cancrids.

Koen Miskotte and I observed the delta Cancrids during mid January  in the
past. They are definitely too slow to be meteors with Vgeo as high as 38
km/s. Something closer to 25 km/s or perhaps even slower would be closer to
reality. I think this is a more serious objection to association with 2001
YB5 than the discrepancy in maximum date, given that the stream profile is
(very) ill defined.

That said, I must add that there is a lot of other slow to medium stuff
visible in January. The stream you point to, might 'hide' among the medium
velocity part of those.

Yet the delta Cancrids are intruiging too. In 1993, on January 16-17 Koen
Miskotte observed a remarkable event of what seems to have been the tail of
a small outburst. Within an hour he saw 8 bright and slow meteors coming
from a  radiant at the Cancer-Canis minor border, very close to the (wide)
delta Cancrid radiant. Most of these meteors concentrated in the first 15
minutes of his observational session. The following years, none of us has
seen activity of this stream at that level (while I watched during the very
same solar longitudes in 1997). We typically noted 1-3 possible delta
Cancrids per hour at best, and most of these faint while almost all of the
1993 meteors were +2 or brighter (with a peculiarly typical outlook of "a
little ball with a tail (wake)").

- Marco Langbroek (DMS)


---
Marco Langbroek                    private: marco.langbroek@wanadoodot nl
Leiden University                     work: m.langbroek@arch.leidenunivdot nl
Faculty of Archaeology
P.O. Box 9515
http://home.wanadoodot nl/marco.langbroek/
NL-2300 RA Leiden
The Netherlands

"What seest thou else
  In the dark backward and abysm of time?"

William Shakespeare: The Tempest act I scene 2
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