Our calculations helped to find meteorites that fell on Christmas Day in Belarus
Our group is known worldwide for its high quality calculations of meteorite impact areas. Last Christmas we were approached by amateur astronomers from Belarus, who have been operating their own network of video cameras for meteor observations for seven years. On the first Christmas Day, shortly after the start of the observing period, 35 minutes after sunset, their three cameras captured the passage of a very bright bolide in a still bright and partly cloud-covered sky (Figure 1). Their own calculations pointed to a possible meteorite fall. The bolide broke up into a series of fragments at the end of its trajactory (Figure 2).
Figure 2: Four individual frames from the video in Figure 1 showing the breakup into fragments. Source: Belarus Meteor Network, Yury Harachka.
We measured the bolide, including fifteen fragments, with our own programs on two video recordings. We’ve confirmed that there was a meteorite fall. The bolide began near Minsk and moved towards the northeast. The cameras recorded it only in its second part, from 48 kilometres below. The last fragment ceased to be visible at an altitude of 19.8 kilometres, approximately above the village of Zhazhelka.
With the help of a wind profile model provided by Dr. Radmila Brožková from the Czech Hydrometeorological Institute, we calculated the meteorite fall area. It starts east of the town of Smalyavichy, where small meteorites weighing from one to ten grams should be located, and stretches for about ten kilometers to almost the settlement of Osinnik, near which the three largest meteorites weighing around one kilogram could be found.
We have sent a map of the impact area to our colleagues in Belarus. The search was initially hampered by snow cover. However, on 20 January the planetarium in Minsk was able to put out a call to local residents to search for meteorites. A number of volunteers eventually joined the search, and meteorite experts from the Ural Federal University in Russia also arrived. The search was successful, with six meteorites weighing between 31 and 230 grams found in the fall area during the weekend of 25-26 January. One of them has already been sent to Ekaterinburg for analysis. The first meteorite found is shown in Figure 3.
Figure 3. Meteorite of a mass of 56 grams found on 25 January. Source: Belarus Meteor Network, Yury Harachka.
These meteorites, which have not yet been officially named, represent the seventh meteorite find on the territory of Belarus and the fourth whose fall has been observed, but the first with a known trajectory. In total, there are now over fifty such meteorites with a pedigree worldwide. About half of them our group was involved in, either by direct observation or at least by calculating the trajectory and orbit, as in this case.
Acknowledgments: We thank Dr. Radmila Brožková from the Czech Hydrometeorological Institute for providing the wind data and Yury Harachka from Minsk for fruitful collaboration.
Jiří Borovička