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Re: (meteorobs) Some Perseids above annual in 2003?
> Esko,
>
> Can you say anything about the brightness of the possible additional
meteors? In a DMS report I read that the maximum night in 1997 started with
some fireballs.
>
> Daniel van Os
This is a misunderstanding, although indeed something unusual did happen on
12/13 August 1997.
I think Daniel mistakes with 11/12 August 1997. There were two Perseid
fireballs seen from the Netherlands within 40 seconds (!) near 1:09 UTC on
August 11/12, close to
passage through the Swift-Tuttle node. This occurred late in the local
night 11/12, but my analysis of the data of that night showed neither a
short-term change in r-value, nor in ZHR for 11/12, so this double fireball
likely was just by chance. It were two out of three notable bright Perseids
of that night.
The following night however, the maximum night, there was a genuine sub-peak
with a duration of about 0.75 hour centered on 23:45 UTC, night 12/13
August. During the peak, rates were about 150% of the normal annual rate for
that solar longitude. This sub-peak was discovered by Rainer Arlt in
IMO-data and shows up well in the Dutch DMS data too. This peak did not
consist primarily of bright meteors however, the brightness was quite
'normal' to perhaps even a bit on the faint side (in fact the r-value
suggests slightly fainter meteors than the previous night), although there
was a nice -5 at 00:07:10 UTC. The peak occurred AFTER local moon set, and
at Biddinghuizen we had a fine clear night, part of a whole series of bright
clear nights.
I have published an analysis of Dutch data for 11/12 and 12/13 August 1997
in WGN of 1997 (I believe, could also be early 1998 perhaps but don't have
it at hand at the moment) and Radiant (J. DMS) of October 1997 and of
course the 12/13 subpeak details can also be found in the IMO Perseid 1997
analysis.
- Marco Langbroek
Dutch Meteor Society (DMS)
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