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Wed, 24 Dec 2014 - Ursid outburst Dec 22-23

Reports have been published via the meteorobs forum of a short lived outburst from the Ursid meteor shower during the night of Dec 22-23. Unfortunately, the UK had widespread cloud cover at the time of this outburst.

This meteor shower, which is active each year between Dec 17 and Dec 25, usually produces a peak ZHR of about 10. Nevertheless, there have been a number of years in the past, including 1945, 1982 and 1986, when a stronger display has been seen. However, whereas strong displays from meteors showers such as the Leonids and Perseids tend to coincide with when the parent comet is near perihelion, there is no such correlation between Ursid outbursts and the position of comet 8P/Tuttle.

Predictions of slightly enhanced activity in 2014 had been made in advance by Esko Lyytinen (for 23:38UT on Dec 22) and Mikhail Maslov (23:54UT), related to a close approach to the Earth by a dust trail ejected by the parent comet in 1405AD. Jeremie Vaubaillon had also predicted that a possible encounter with a 1392AD dust trail might lead to slightly enhanced activity around 00:40UT on Dec 23. The observed rates reported indicate, however, that the display was somewhat stronger than predicted, with the peak ZHR possibly briefly reaching 50. The reports published so far indicate that the peak occurred within 30 mins of Dec 23d 0h UT, with rates back down to "normal" levels within a couple of hours. Hopefully, more detailed analyses, including data from radio monitoring, will allow the peak time to be defined more precisely.

As often happens after an outburst of activity from a meteor shower, the observing conditions for the next annual display are somewhat less favourable. The 2015 Ursid peak is set to occur only 2 days before Full Moon and there will only be about an hour of dark skies between moonset and the onset of morning twilight.


Added by: Tracie Heywood