Bright fireball of 17 January 2002

Dutch-German border area

Bright fireball sighting, 17 January 2002

In the evening of 17 January 2002, a very bright fireball occurred over the German-Dutch border area. This fireball was bright enough to illuminate the surroundings, even though at most observing localities a thin cloud cover was present! One observer's attention was attracted to the fireball because he suddenly saw the surroundings light up. This fireball must have been of order -10 to -15 magnitude, comparable to the full moon in brightness.

Green and white colors were reported for the fireball, which was rather slow. In addition, two observers report fragmentation in at least two separate pieces, while a third observer reported possible fragmentation. Hence, fragmentation seems to be well established for this fireball. One observer reports a short persistent train nothwithstanding the thin cloud cover.

Trajectory analysis of initial reports suggested a possibly very low atmospheric end altitude of ~30 km, leading to a "red meteorite dropper allert" within our research group. A later revision of the trajectory, after receipt of more data, however shifts the altitude of extinction for this fireball considerably upwards, to about 50-60 km altitude, making a meteorite fall less likely. The possibility of a space junk decay could be dismissed right away. The bolide was too fast for that.

Sightings

- The first sighting was received from Dutch DMS meteor observer Paul van der Veen who noted the bolide while on his bicycle in Eindhoven. For him, the fireball appeared to move southeast to northwest (direction of movement rather than directions of sighting), passing high overhead. He logged 19:15:22 +/- 2 seconds UTC as the appearance time for the fireball. The duration was estimated at 2 seconds.

Other sightings were received from:

- Mr. Meessen and daughter from Wylre, Dutch Limburg. They noted the fireball starting from 45 degrees altitude in the northeast and extinguishing due north at 30 degrees altitude. They noted a green color, short persistent train and possibly some fragmentation. Time is given as 20:14 MET, or 19:14 UTC. The duration was estimated at 6 seconds

- Mr. Froyen from Rotem, Belgian Limburg. He saw the fireball first appearing northeast and ending due north, at about 45 degrees altitude. A white color was noted. Because his attention was put to the fireball when the surroundings lit up, this observer probably saw part of the trail only. Time is given as 20:13 MET, or 19:13 UTC. The duration was estimated at 2-3 seconds.

- Mr. Van der Linden from Utrecht, Netherlands. This observer also observed the fireball while on his bicycle, seeing it right in front of him, and the direction of the street through which he drove at the moment provides guidance to the observed directions. Fragmentation is reported, and a white color. Time is given as 20:15 MET or 19:15 UTC. A duration of 1 second was estimated.

Through the efforts of André Knöffel (FIDAC, IMO), we obtained two sightings from Germany which likely concern this fireball. Directions and fireball characteristics are in agreement with the Dutch/Belgian sightings, but the appearance time for both sightings is given as 19:45 UTC and thus deviates by 30 minutes:

- Mrs Weyres from Dusseldorf, Germany. This observer saw the fireball in the northwest, and noted a green color and fragmentation into at least two pieces. The duration was estimated at 4 seconds. Brightness is given as "as bright as the full moon".

- Mr. or Mrs. Bunke from Gelsenkirchen Buer, Germany. Only a global direction, "west", is given, and "very bright".

Apart from these sightings, we received through Vincent Jacques, Belgium, a sighting of a fireball "as bright as the full moon" seen "north", from Clermont-Ferrand, central France. We also received a note from the public observatory at Lattrop, the Netherlands, that the fireball was seen from Lösser, Twente (east Netherlands) but all further details are lacking for this sighting.

Trajectory

The resultant trajectory is not too well defined. Best established is the location of the endpoint, which is in the eastern part of Dutch Brabant, in the area bounded by the villages of Veghel, Cuijk and Venray. The atmospheric altitude of extinction was probably in order of 50-60 km. The starting point is ill defined. Either Dusseldorf or Utrecht provides a strongly deviating azimuth of the starting point. Because of the general directions for the Eindhoven and Gelsenkirchen sightings, and because the Utrecht values appear to be more uncertain, the Dusseldorf value has been preferred in the current analysis, leading to the trajectory designated by a thick arrow in above pictures. The thinner dashed line to the north of it gives the possible trajectory if instead the Utrecht value is more correct.

Velocity

The favoured trajectory has a length of about 50 km. Combined with the duration estimates, this points to a velocity of order 15-25 km/s. With an average duration estimate of 2 seconds, a velocity <20 km/s is likely.

Radiant: a delta Cancrid?

The radiant is very ill defined due to the large uncertainties in the trajectory azimuth. The favoured trajectory (azimuth ~ 100-105 degrees) and the entry angle as seen from Wylre (15-20 degrees), indicate a radiant low in the southeast, in the Canis minor-Cancer area. This is where the radiant area of the delta Cancrid minor stream is located, a stream which peaks around January 17. Delta Cancrids have a velocity of ~28 km/s, which is just slightly above the (highly uncertain) value for the 17 January 2002 fireball. The stream is known to give bright meteors on occasion, for example the sightings of several bright and sometimes fragmenting stream members by Koen Miskotte on January 16-17 1993. Interestingly, asteroid 2001 YB5, an earth crossing asteroid which had a very close passage to earth only 10 days prior to the fireball appearance, also provides a theoretical radiant in this area.

Acknowledgement

We thank all the observers who reported their data. André Knöffel and Vincent Jacques are thanked for communicating the German and French observations. We thank Dr. Pavel Spurný (Ondrejov, Czechia) for communications on possible detections by camera's and photoelectric timers of the EN network, and for enquiring about infrasound detections. We thank Dr. Laslö Evers (KNMI, the Netherlands) for communications about possible infrasound detections.

Text and analysis by Drs Marco Langbroek and Ing. Casper ter Kuile, Dutch Meteor Society. Contact: meteorites@dmsweb.org. See also: www.dmsweb.org