On 2010 October 13, the Apollo type 20-meter asteroid 2010 TB54 passed within 6.1 lunar distances from the Earth. On the same date, but 11.4 hours earlier, exactly at 02:52:32 UT, the sky over central Poland was illuminated by -8.6 magnitude PF131010 Ciechanow fireball. The trajectory and orbit of the fireball was computed using multi-station data of Polish Fireball Network (PFN). The results indicate that the orbit of the meteoroid which caused the PF131010 fireball is similar to the orbit of 2010 TB54 asteroid and both bodies may be related. Moreover, two days before appearance of Ciechanow fireball another small asteroid denoted as 2010 SX11 passed close to the Earth-Moon system. Its orbit is even more similar to the orbit of Ciechanow fireball parent body than in the case of 2010 TB54.
The PF131010 Ciechanow entered Earth's atmosphere with the velocity of 12.9 +\- 0.2 km/s and started to shine at height of 82.5 +\- 0.3 km. Clear deceleration started after first three seconds of flight, and the terminal velocity of the meteor was only 5.8 +\- 0.2 km/s at height of 29.3 +\- 0.1 km. Such a low value of terminal velocity indicates that fragments with total mass of around 2 kg could survive the atmospheric passage and cause fall of the meteorites. The predicted area of possible meteorite impact is computed and it is located near Grabowo village south of Ostroleka city. The results are presented in the paper "PF131010 Ciechanów fireball - the body possible related to Near Earth Asteroids 2010 TB54 and 2010 SX11", accepted for publication in the Monthly Notices of the Royal Astronomical Society (MNRAS). The authors: A. Olech (Nicolaus Copernicus Astronomical Center in Warsaw), P. Żołądek, M. Wiśniewski, R. Rudawska, J. Laskowski, K. Polakowski, M. Maciejewski, T. Krzyżanowski, T. Fajfer i Z. Tymiński.
Picture: The PF131010 Ciechanow fireball. Photo taken in Nowe Miasto Lubawskie (Credit: PFN/PKN)
