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(meteorobs) Reminding

Hi, everyone,

I just noticed that there has been someone observing for early Leonids. So I would like to remind you that the new meteor shower (iota-Aurigids) can be monitored from now on. The coordinate and parameters of this meteor shower was mentioned in the observing call below. I hope you can pay attention to telling the members of it from the sporadic streams, and send a copy of your observational reports to iau_shower@hotmail.com. All the reports will be welcomed.

All best wishes and Clear skies!
Huan Meng  <meteorobs_menhu@hotmail.com>


>>---------------------------------------
CALL FOR OBSERVATIONS FOR IOTA-AURIGIDS
by Huan Meng

The iota-Aurigids were first discovered by D. Koschny and J. Zender of
the European Space Agency in 1998. They found a suspected radiant at
right ascension 75 degrees (+/- 1 degree) and declination +37 degrees
(+/- 2 degrees) while obtaining video data of the Leonids from the
Netherlands in 1998. The results of the "possible new radiant" was
published in WGN, the journal of the International Meteor Organization
(WGN, Vol. 27, No. 1, pp. 51-52).

Independently in 1998 and in 1999, a group of observers lead by H. Meng
observed the Leonids from China. Their plots recorded possible members
of this new shower, but it remained unnoticed until 2000. In H. Meng's
visual counting observation of the Leonids in 2000, he noted an unusual
number of meteors that came from the "northern sky". By reviewing the
plots from the past two years, a radiant was found at right ascension 76
degrees (+/- 5 degrees) and declination +36 degrees (+/- 5 degrees). The
new meteor shower was then named the iota-Aurigids.

Some parameters were obtained by these initial plots as well as plots
that were collected later. The population index of the shower was
determined to be r = 1.5 (+/- 0.9) without considering the probabilities
of perception (r = 2.4 (+/- 1.0) when considering the probabilities).
Under the situation of r = 1.5, we obtained the highest ZHR-values of
ZHR = 14.5 (+/- 10.9). As the effect of probabilities of perception is
excluded, the true value of the population index must be higher than
1.5. The ZHR's true value then may rise to 20 or more. Finally, from
video data obtained at the IMO's website, we were able to obtain a
geocentric velocity of V = 46 km/s.

We also searched for the parent comet of the shower, but no known comet
matched the parameters of the shower perfectly. We did notice that
C/2000 LINEAR WM1 (Christmas-day Comet) was a possibility. In the
hundreds of comets which were investigated, it's radiant and geocentric
velocity was the nearest match to that of the shower. But the difference
between the observed coordinates and the computed ones for  LINEAR were
a bit large, about 20 degrees. And it was too far away (about 10
astronomical units) from us when we may have observed the dust (meteors)
from it. As a result, we're not sure if there is indeed a relation
between the meteor shower and Comet LINEAR. (Note that this coming
November, C/2000 LINEAR WM1 will pass the nearest point to the Earth's
orbit only 16.7 days earlier than the Earth!).

New observations of this possible meteor shower will be very important.
The activity period is generally between lambda = 230 and lambda = 240,
i.e. November 13th to November 22nd. We predict two peaks this year. The
first one will appear at about lambda = 234.0 with a ZHR = 15. The
second one will appear at about lambda = 235.8 with the ZHR = 20. But
this is a prediction only, so all observations from lambda = 233 to
lambda = 237 will be critical. The time before the Leonid maximum is
especially suited to monitoring activity from the iota-Aurigids.

If you are able to monitor possible activity  from the iota-Aurigids
during your November observations, please send your report to the IMO
and provide a copy to the email address set up specifically for these
reports. We are interested in hearing from observers with either
positive or negative results. Reports may be sent to:

iau_shower@hotmail.com

[H. Meng has completed a special paper discussing this meteor shower,
but unfortunately, it was too late to be published formally in any
journal. That paper will be published at a later date. All of the
content above was provided by H. Meng and is from the upcoming paper.] <<




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