Possible Taurid Complex 'Swarm' Return in June

by Alastair McBeath

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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 and Fireball Data Center respectively (see http://www.imo.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://www.nlcnet.co.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.
E-mail: vice_president@imo.net