The team studied 144 large meteors from the Taurids, a meteor stream which appears in our skies twice a year. The group discovered a new branch of the phenomenon containing at least two asteroids measuring a whopping 200-300 meters (220-330 yards) in diameter.
This branch likely includes even larger undiscovered asteroids, according to a statement from the Academy of Sciences of the Czech Republic.
The Taurid meteoroid stream produces at least four meteor showers over Earth: two are active from the end of September until the beginning of December, and two from the end of May to the middle of July.
Earth encounters the newly discovered branch every few years for about three weeks. Scientists say that during this time the chance of an impact with a sizeable asteroid – measuring up to tens of meters – is significantly greater.
The meteors analyzed by the Czech astronomy team were from 2015 when the stream’s activity was enhanced. Details of the study are published in Astronomy & Astrophysics,
The new digital autonomous observatories of the European Fireball Network spotted the fireballs over Czech Republic (at 13 stations), Austria (1 station) and Slovakia (1 station).
The researchers say further study is vital to gain a better understanding “of this real source of potentially hazardous objects,” warning that the meteors could cause significant regional or even continental damage.