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(meteorobs) Possible Taurid Complex "Swarm" Return in June
POSSIBLE TAURID COMPLEX "SWARM" RETURN IN
JUNE
This is a reminder to all observers of (now IMO
Council member) David Asher's prediction of a possible return of the Taurid
Complex (TC) 7:2 resonant "swarm" of larger or more numerous meteoroids in June
2002 either during the Zeta Perseids or Beta Taurids. These are two daytime
meteor showers with radiants too close to the Sun to be observed visually from
Earth. Consequently, any enhanced activity is most likely to be detected by
radio or radar methods only.
However, there is the very slight chance that
visual observers might pick up an occasional daylight fireball due to this
"swarm" return as well, or perhaps one in twilight near dusk, or more possibly
towards dawn. As yet, no definite daytime fireballs from either source have been
recorded, but David reminded me a few days ago that a series of tonnes-weight
boulder impacts were recorded by NASA's Apollo mission lunar seismometers in
late June 1975, hypothesized by several authors since as belonging to the Beta
Taurid stream. David further commented: "If the 7:2 swarm idea is correct, then
the period is 3.39 years (as can be immediately calculated knowing Jupiter's
period) and so 8 revolutions after 1975 brings you close to 2002 (deviation only
0.1 year). So as long as the density doesn't suddenly fall off within just
0.1 year along the supposed swarm, this suggests something should be there (if
the model's correct)."
The most plausible time for anything unusual to
happen is ~5-8 days before the often ill-defined Beta Taurid peak around June
28, thus between June 20-23, but any radio/radar meteoric enhancement could be
quite minor, and its timing within either the Zeta Perseids (active from May 20
to July 5, maximum June 9 or 10) or Beta Taurids (active June 5 to July 17) is
unknown. An earlier suggested "swarm" return in 1999 June produced nothing
conclusive, but another prediction during the night-time Taurids of
October-November in 1998 was apparently confirmed by visual and radio observers
in the closing days of October. The Earth will pass similarly close to the
centre of the theoretical swarm in 2002 June to 1998 October-November. The lunar
impacts in 1975 spanned a roughly ten-day interval centred on June
22.
Other, non-meteoric, events may be detected as a
result of the "swarm", possibly including enhanced Sporadic-E (Es) radio
propagation or noctilucent cloud (NLC) displays. Both seem to be at least partly
created by meteoric dust or ions in the upper atmosphere, although Es or NLC may
occur only some time (perhaps a few days to a few weeks) later. An unusual
meteoric event might produce more immediate results, however.
Observers should report their data as usual during
June. IMO-standard visual results and fireball sightings should go to the Visual
Commission <visual@imodot net> and
Fireball Data Center <fidac@imodot net>
respectively (see http://www.imodot net for
observing and reporting advice). Radio result summaries, including details of
all Es events, should go to the Radio Meteor Observation Bulletins (http://www.rmob.org). NLC observations should go
to Tom McEwan - see http://wwwdot nlcnet.codot uk for details on how,
what and where to submit your data. I would appreciate a cc of any data you
consider unusual and possibly linked to the TC "swarm" return, though I will
also pick up details of reports submitted to the above places.
More notes on both daytime showers, including
radiant positions, can be found on the IMO's website, or, with some additional
relevant discussion, on the 2002 June "Meteor Activity from Britain" page among
the Meteor Section's part of the Society for Popular Astronomy's website, http://www.popastro.com/sections/meteor.htm.
For past references concerning the TC "swarm" see my article in the IMO's
journal "WGN" 28:1 (February 2000), pp. 21-29, "Daytime Taurid Complex Stream
Activities, May-July 1999: A Provisional Report".
Good luck for all your observing, and clear
skies!
Alastair McBeath,
IMO Vice-President & SPA
Meteor Section Director.