The broad background peak of activity of this year's Leonid meteor shower is expected to occur around dawn on the 17th November. The meteors, or shooting stars, are produced by particles shed by periodic comet Tempel-Tuttle, each time it makes a fly-past of the Sun approximately every 33 years. During each passage of the Sun, the comet emits a stream of dust and small particles, which can remain coherent for centuries, before dispersing.
Prospects for the Leonid Meteors November 2004
Each year the Earth encounters the ancient dispersed stream of material during mid-November. It is anticipated that rates will be up to about 50 meteors per hour for a few hours around peak activity, under ideal conditions. Leonids are fast meteors, travelling at 160,000 miles per hour, and many of them leave persistent trains. Conditions this year will be favourable in that there will be no interference from the light of the Moon.
According to Armagh Observatory astronomer, David Asher, and co-workers, there will be two additional peaks of activity after the broad stream peak. The Earth will encounter the outer parts of the stream emitted by the comet in the year 1333 around 6.40am on 19th November. However, rates are only expected to be about 10 per hour at maximum. Eastern America is well placed for this shower.
The second peak occurs around 10pm on 19th November when the Earth passes through the fringes of the stream emitted in 1733. A peak rate of about 60 meteors per hour is expected. For Northern Ireland viewers, the radiant in the constellation Leo, that is, the place from where the meteors appear to diverge, will be on the northeastern horizon. Under clear skies, the meteors will be seen to rise upwards from the horizon. The radiant's low elevation in the sky around 10 - 11 pm means that observed meteor activity will be lower than the 60 meteors per hour expected in ideal conditions.
Observations of this year's display will help to further refine the calculation of activity levels from this meteor shower. Observers are advised to wrap up in plenty of layers of warm clothing and view from a dark, preferably elevated, site.
FOR FURTHER INFORMATION CONTACT: John McFarland at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3755-7174; jmfstar.arm.ac.uk
Leonid Meteor Pages
The unexpected 2004 Leonid meteor shower - PDF Format
Last Revised: 2004 November 15th
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