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(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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