Cometary avalanches as the cause of their violent outbursts - a new model of the phenomenon

Abstract

The cometary outbursts are one of the most spectacular phenomena one can observe in the sky. They are associated with a sharp increase in the brightness of comets, which arises as a result of the ejection into space the dust, gas or even the fragments of outer layer of these celestial bodies core. Despite the existence of extensive observational material, as well as many proposed hypotheses trying to account for this phenomenon, the problem has not been definitively resolved up to these days. The main reason is the looking for a processes that could be responsible for the destruction of surface of the cometary nucleus. This paper considers the occurrence of local cometary avalanches as possible mechanism which may be responsible for the formation of depression or landslides of cometary material. The mechanism is proposed based on the analysis of numerous pictures taken by the Rosetta space probe during its mission. Our main goal is to determine the change in comet brightness using the proposed avalanche mechanism. In addition, the comparison of accuracy the simplified formulae describing the glow of comets during their outbursts with the new one, derived by the authors is also presented here.