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Re: (meteorobs) Perseids prediction
Just adjusted the ejection velocity. It seems that the new result is not
consistent with the one from simplified algorithm.
The expected population index should be 2.75, instead of 2.16 as stated
previously.
There must be something wrong with the last conversion of the Perseid and
Leonid parameters. Although, now, the conversion relation is not very
certain still.
Huan
----- Original Message -----
From: "Huan Meng" <meteorobs_menhu@hotmail.com>
To: <meteorobs@atmob.org>; <imo-news@yahoogroups.com>
Cc: "Jeremie Vaubaillon" <vaubaill@imcce.fr>; "Esko Lyytinen"
<esko.lyytinen@luukku.com>
Sent: Saturday, August 09, 2003 9:55 PM
Subject: (meteorobs) Perseids prediction
> I have sent my confirmation result of Esko's prediction in the other day.
> But in fact, we used the same orbit but different model. Viewing the orbit
> used by Jeremie, Esko pointed to Jeremie and me that there might be
probably
> a mistake. So, it will not be a surprise to caught a real peak at 0h UT,
> August 13.
> (The orbit used by Jeremie indicates a perihelion time of AD527 instead of
> AD569. I have checked the Chinese historical records of bright comets, but
> there are neither any corresponding records in 527 nor 569.)
>
> Just now, I tried calculating the population index of Perseids this year
> with my new-derived model. After last Leonids, I have worked for this
model
> with some colleagues. But more uncertainty maintains for Perseids than for
> Leonids. It is because global observations in recent years have obtained
all
> necessary parameters from the close encounters of Leonid dust trails with
> our earth, while, more Perseid parameters are unknown. In addition, this
> model is based on previous data, and have never been used for predictions.
> Now, following some reasonable assumptions, the model was performed for
> Perseids this year. The peak time was computed with David Asher's ejection
> model with slight experienced modification. And the
> full-width-at-half-maximum (FWHM) was calculated from an idea of mine,
which
> is going to be evaluated by an upcoming Monte Carlo simulation.
>
>
> As the result of my computation, the peak will occur at 00h09m UT, August
> 13; another possible minor peak may appear at 00h39m UT on the same day.
> They were caused by the dust trail ejected from the parent comet 109P in
its
> perihelion passage in AD569. The missing distance of their geometric
center
> with the earth were 0.0009 au and 0.0014 au, respectively. Comparing with
> the case of Leonids, I suppose the ZHR adding to the background may be
> 20-80. In my model, the real-time population index (r) may be 2.16 at the
> maximum POINT. (Note that the r-value is a function of time!) The FWHM may
> be 53 minutes.
>
> I will leave for Xinglong for observations tomorrow. Meanwhile, I plan to
> pay attention to determining the LM before the twilight when the milky way
> is still visible :-)
> The Perseids this year is not favored by the bad moon phase. However,
> observations will be important as well, for recognizing the correct
> historical orbit of the comet, evaluating the model of population index
etc.
>
> Best regards, and Clear skies,
> Huan
>
>
>
>
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