Potential meteorite fall on Polish-German border on Jan 22, 2022

(reported by Pavel Spurný, Jiří Borovička, Lukáš Shrbený, Ondrejov Observatory, Czech Republic).
Original article: https://www.asu.cas.cz/~meteor/bolid/2022_01_22/index.html

On the evening of Saturday, 2022 January 22, shortly before 8 pm CET, a very bright fireball passed north of Poland. Unfortunately, it was cloudy in most parts of Central Europe at that time, so that there were only very few casual witnesses, and the fireball remained hidden behind the clouds for the most of instruments designed for fireball tracking. Nevertheless, it was recorded photographically at the Frýdlant station in Bohemia (Figure 1), which was the closest to the bolide’s path of the video stations, and then from the distant Rimavská Sobota station in Slovakia. In addition to the photographic images, its passage was recorded by a special video camera again from Frýdlant and also the end of its trajectory from another video camera located at the observatory in Jičín. In addition, the exact light curve of the bolide was recorded using very fast photometers from all nearby stations of the bolide network, also those with cloudy sky. These unique instruments, which are also part of the cameras network, recorded bolide light in all kinds of weather. They have a temporal resolution of 5000 samples per second and are used both to accurately determine the bolide’s transit time, its brightness and to model its fragmentation in detail as it passes through the atmosphere. So both the atmospheric trajectory and its orbit in the Solar System are known.

Figure 1- The all-sky image taken by the Frýdlant station in Bohemia shows the fireball of 2022 January 22. (photo: Astronomical Institute of the CAS).

The fireball reached nearly the brightness of the full Moon (at a standard observation distance of 100 km) and it penetrated deep into the atmosphere, suggesting that meteorites reached the Earth’s surface. Checks were conducted to get any other instrumental record that could complement our data. One video record from the AllSky7 system was found, as it’s also designed to record bright meteors. The leader of this project, Mike Hankey, very helpfully sent us this footage, taken by the operator Peter Lindner from Hoyerswerda, Germany, and although there is a portion of the bolide behind the clouds, it greatly increased the accuracy and weight of our original results.

So what exactly happened on the evening of Saturday 22 January over western Poland?

At exactly 18h 48m 57s UT, a meteoroid, the size of a basketball and weighing approximately 25 kg, entered the Earth’s atmosphere. The luminous path started at an altitude of 90 km above the ground north of the Polish city of Swiebodzin. At that time, the body was moving at a speed of less than 17 km/s and continued its flight in an approximately westerly direction along a path inclined at 49 degrees to the Earth’s surface (Figure 2). Its brightness increased rapidly and for about 2 seconds even reached almost the brightness of the full Moon. The bolide brightened several times during the flight, reaching its maximum brightness at 37 km above the Earth during one of these brief brightenings, when the body fragments in the atmosphere. At this stage of the flight, the meteoroid was fragmenting significantly in the atmosphere. The entire luminous trail of almost 92 km was passed within 6.7 seconds. It terminated very deep in the atmosphere at an altitude of 21 km at a speed of just over 3 km/s near the German-Polish border near the Polish town of Kostrzyn. The expected meteorite fall should have occurred south of this town and the meteorites may lie on both sides of the border formed by the Oder River. The larger meteorites, the main piece of which may weigh up to one kilogram, are located in the north-western part of the marked area in Germany (Figure 3). Smaller meteorites weighing less than 200 grams have already fallen on the territory of Poland. The total mass of the meteorites may be around two to three kilograms.

The meteoroid orbited the Sun in an ellipse with a very small inclination within 2.4 years with its aphelion in the asteroidal main belt.