A prediction of the collisions of Main Belt asteroids with stream meteoroids

Asteroids and comets belong to the small bodies of the Solar System. In the past, it was thought these categories were clearly distinguishable. Then objects with dynamically asteroidal orbits, but comet-like activity started to be discovered. This class of objects is also known as active asteroids. The activity of comets is caused by the sublimation of ice and accompanying dust removal. In the case of active asteroids, several possible mechanisms of activity accompanied by a mass loss are discussed. A meteoroid impact can also trigger observable activity. It is more likely that such a collision would involve a stream meteoroid which moves around the Sun in a corridor with a relatively much higher density of meteoroids than the density of sporadic meteoroids. In this work, we mapped the passages of the main-belt asteroids through the corridors of known meteoroid streams. By considering all of the reliably known main-belt asteroids and all of the mean orbits of known meteoroid streams, we found over 232 million of passages. A list of the dates of passages is provided for a period of the next ten years. In future, if an outburst of initially inactive asteroid occurs, one can quickly find whether the asteroid crossed any of the known meteoroid streams shortly before the outburst or not and hence evaluate whether the collision with stream meteoroid could be a possible trigger. In addition, we dealt with the determination of the enhanced probability of a collision between an asteroid in the main belt and a meteoroid which is a member of meteoroid stream. Firstly, we estimated minimum probability of collision of asteroid with meteoroid by considering the minimum flux. In this case, if meteoroids with masses larger than 10 kg were considered and if the typical radius of asteroid was 200 m, the mean time between two collisions would be about a century. Further, another probability estimate was made by identifying the known flux of Perseids with the flux of “mean” meteoroid stream. For typical radius of asteroid equal to 100 m and in case of meteoroids larger than 100 kg, we would get approximately 10-320 years as a mean period between two collisions. And this period would be shorter than about 10 years if the typical asteroidal radius was 500 m. Our estimates of the probability for some reasonable values of free parameters imply that a meteoroid impact cannot be excluded as a mechanism triggering the comet-like activity of a significant amount of known active asteroids. We cannot exclude, either, that the impact is the dominant mechanism of this triggering.