(meteorobs) Questions on september radiants

[Nikola Bilišskov]

Karl Antier wrote:
> Hi all meteor observers !
>
> Here are a few questions...
> Thank you in advance to all of you that'll take the time
> to answer !
> First, I read on Gary's Kronk webpages Meteor Showers Online,
> that the alpha-Aurigids were probably linked to the comet
> Kiess (1911 II), which has a nearly parabolic orbit. Has
> anyone found an explanation to explain why outbursts always
> occur, even 75 or 83 years after its passage to perihelion ?
> How is it possible that a single comet passage give birth
> to such a regularly active meteor shower ?
>   
During time, meteoroids spread all along the comet's orbit. Just very 
young meteoroid streams are located just in the environment of the comet.

> Second, according to the same source, delta-Aurigids (and I
> guess, the newly named September Perseids) find maybe their
> origin in comet Bradfield (1972 III). The website of the IMO
> speaks of a possible complex of streams in Aries-Perseus-Aurigae-
> Cassiopae. Can anyone tell me which streams are part of this 
> complex ? Delta-Aurigids or alpha-Aurigids ? What are the 
> coordinates of the suspected other showers that have been
> observed once by the past, and never recovered since ? Does
> anyone know what the source of this complex ? Comet Bradfield
> or Kiess ?
>   
It's comet Bradfield. Delta Aurigids are part of this complex.
> And my last question for the moment deals with the Antihelion
> radiant : what is it really due to ? I thought it was the
> particles of the ecliptic that were at its origin ? Is it right ?
> In that case, why does it seems to originate from the Antihelia
> point ? Shouldn't it be slightly shifted due to the Earth rotation
> or revolution around the Sun ? And has anyone ever observed visually
> a meteor coming from the Helion source (earthgrazer, I imagine...) ?

Antihelion radiants are very complicated set of radiants located near 
the ecliptic. Their origin is also cometary, but, because of the 
stronger influence of large planets, these radiants are generaly fuzy 
and complex. Before, these radiants were observed as individual streams, 
like Virginids etc.
Nikola