Location of upper borders of cavities containing dust and gas under pressure in comets

Abstract

The distance between the pre-impact surface of Comet 9P/Tempel 1 and the upper border of the largest cavity excavated during the ejection of material after the collision of the impact module of the Deep Impact (DI) spacecraft with the comet is estimated to be about 5-6 m if the diameter of the DI transient crater was about 150-200 m. The estimated distance is 4 m if the diameter was 100 m. This result suggests that cavities containing dust and gas under pressure and located a few metres below the surfaces of comets can be common. © 2012 The Author Monthly Notices of the Royal Astronomical Society © 2012 RAS.