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(meteorobs) PD: ?P/2001 Q2 and Fireballs?

Hi all!

Below I attached mail from John Greaves about new comet
P/2001 Q2 (Petriew) and possible meteors from comet.

Best regards,
Maciej



>
> Please note that the following is based on an orbit for P/2001 Q2 that is
> at present based on only a two day orbital arc.  There's a small amount of
> "black box" worked involved here, and a lot of the following has not been
> rigorously checked as yet, and is mostly of a circumstantial nature.
> Anyway, I present it for people's interest, feel free to do with it as you
> will and pass it on as you desire.
>
>
> MPEC 2001-Q31 gives the first published orbit of P/2001 Q2 (Petriew)
>
> The orbit is remarkably similar to that of 103P/Hartley 2, especially the
> 1997 orbit of the latter.  The orbit of 103P has evolved a little due to
> close approaches to Jupiter of around 0.4 AU in Dec 1993, 0.3 AU in Nov
> 1982 and possibly one of <0.1 AU in 1971.
>
> Working the current published orbit of P/2001 Q2 back in time suggests a
> close approach to Jupiter of 0.2 AU in Jul 1982.
>
> To reiterate, the 1997 103P orbit works back to a close approach of
Jupiter
> at 0.33 AU in early Nov 1982 whilst the current published (preliminary)
> orbit of P/2001 Q2 works back to a 0.21 AU close approach to Jupiter in
> late Jul 1982, based simply on gravitational constraints.
>
> The orbits are currently quite similar, save for the fact that currently
> 103P is nigh on aphelic whilst currently P/2001 Q2 is nigh on perihelic.
>
> P/2001 Q2     : q 0.94750  , e 0.69628  , i 14.092  , peri 182.294  , asc
> 214.357  , T 2001/09/02.186
> 103P in 1997 : q 1.031758, e 0.700360, i 13.6197, peri 180.7230, asc
> 219.9543, T 1997/12/21.9
>
> Is P/2001 Q2 a "lump" of 103P?  Who knows... ...sounds daft at first
> thought.  I am reminded of Jennisken's "far" outbursting meteor showers
> here, however, that is meteor showers that he identified as being at their
> most active here on earth when the parent comet was near aphelion.  Said
> aphelia, as in these cases, tend to coincide with Jupiter's orbit, so
> dynamically I suppose it isn't impossible.
>
> Okay.
>
> I went on to use Neslusan's meteor prediction's program to see if any
> shower was suggested... ...using the current orbit given for P/2001 Q2
> gives the following possible radiant details for the pre-perihelic arc of
> the orbit:-
>
> 2000       2000
> RAdeg    Dec    Vgeo   Vhelio   Sol Long    Date              D-disc
> 295         30.3   12.25   38.91    214.4         OCT. 27.7     .046
>
> and, what is more, these values are generated by three of the six
> adjustment methods used.
>
> The statistic D-disc is based on Southworth & Hawkin's D criterion, where
> 0.1 is deemed a decent value, and values less than that threshold
> increasingly more likely as the value decreases.
>
> This in itself means nothing, or course.
>
> For a start there is (to my knowledge) no known Cygnid shower in October.
>
> It then makes sense to check the respective meteor orbits' archives, and I
> used Drummond's D' criterion to statistically test the IAU photographic
> orbits' archive, the IAU radio orbits' archive, and a cobbled together
> fireball archive that I've amalgamated containing orbits from the Prairie
> Network, European Network and MORP network archives.
>
> Drummond's D' statistical criterion is taken usually to have a threshold
of
> around 0.1, such that objects tested against each other that give values
> equal to 0.1 or less are increasingly felt more likely to be related as
the
> value decreases (tends towards zero if you prefer).
>
> There are 3 Morp fireballs with D' of between 0.08 and 0.10, 4 European
> Network fireballs with D' between 0.06 and 0.09 and 14 Prairie Network
> fireballs mostly within the D' range of 0.08 to 0.10: all when  compared
> against the orbit of P/2001 Q2.
>
> (There's also about a dozen or so other non-fireball orbits from the
> photographic archive that match)
>
> Still the dates of these fireballs stretch from late September to early
> November, so it is not a tight relationship, further most of them predate
> any putuative 1982 "shism" event.
>
> However, the following two Prairie Network fireballs, dated 1 Oct 1967 and
> 22 Sep 1974 respectively, have D' values of 0.06 when tested against
P/2001
> Q2, and the following orbital details should be compared to those of
P/2001
> Q2 as given above, and the radiant details also compared to the above
> prediction for P/2001 Q2 (RA and Dec in these instances are epoch and
> equinox 1950).
>
> Code               RA     Dec  Vgeo    q         ecc      incl.   peri.
> asc.
>
> '39764 168F'  308.8 36.3  14.71    0.956  0.666   18.1  207.4  187.1
>
> '42312 318F'  309.5 23.1  13.79    0.940  0.690   13.7  212.3  178.5
>
>
> No doubt this will all have to be looked at again when the orbit of P/2001
> Q2 is well known.
>
> Cheers
>
> John
>
> John Greaves
> UK
>
>

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