FIREBALL OVER NORTHERN BRITAIN

from the 

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The SOCIETY for POPULAR ASTRONOMY

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Electronic News Bulletin No. 281   2010 January 31

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JANUARY 16 FIREBALL OVER NORTHERN BRITAIN

By Alastair McBeath, SPA Meteor Section Director

Three observations of a bright fireball seen around 22:45 UT on January16-17 have been received, two from the Wirral peninsula (where themeteor passed almost overhead) and one from Shropshire. 

 

Informationprovided by the lucky witnesses has suggested the object probably flew above parts of north Wales and northern England, on a roughly WSWto ENE track, and that the meteor was almost grazing the atmosphere,producing a long visible trajectory. 

 

The start has not been well-established so far, but assuming a height of between ~120-100 km altitude suggests the fireball may have first become visible overCaernarfon Bay, about 35 km off the northern Lleyn Peninsula coastof Gwynedd, likely near 52.9°N, 5.1°W for a ~120 km altitude start,or 53°N, 4.8°W for a ~100 km start. 

 

From there, it passed over the extreme north of mainland Wales, from roughly Caernarfon to Point ofAyr, then across the mouth of the Dee to the northern tip of the Wirral in northwest England (plausibly between West Kirby to Birkenhead),above the Mersey, Liverpool (likely a little south of the city centre) and the Pennines of the Lancs-Yorks border northeast of Manchester-Oldham, and somewhat south of Leeds, to end around 75 km altitudenear Mickletown on the River Aire, midway between Castleford andRothwell southeast of Leeds (above approximately 53.7°N, 1.4°W). 

 

Assuming this trajectory was correct would imply the entry angle was very shallow, between ~6° to ~11° from the horizontal, giving an atmospheric path length from ~246 to ~269 km. The observers estimated the meteor was visible from 5 to 8 seconds, whose average

(~6.5 seconds) would indicate an atmospheric velocity, not allowing for deceleration, of ~38-41 km/sec, so about medium-speed on the 11 to 72 km/sec atmospheric velocity scale for meteors. The outlying range for this rough velocity would be ~31-54 km/sec. Some fragmentation along the path was seen, with the colours noted as mainly yellow or white. 

 

The very high end height and the significant fragmentation would both count against any meteorites surviving and being recovered, while the shallow approach-angle makes it almost impossible to define where any such falls could have happened; perhaps into the eastern North Sea, the Baltic, or nearby parts of southern Scandinavia, as a best-guess. No reports of any such falls have been received as yet.

Any fresh sightings of this fireball, or others seen from the UK and nearby, would be welcomed by the Meteor Section. See the "Making and Reporting Fireball Observations" page of the SPA website, at: http://snipurl.com/u8aer, for details of what information to send, and to where.