[P-PS05] Recent advances in the science of Venus

[PPS05-10] Bolide-triggered cloud formation in a planetary atmosphere

*Kevin McGouldrick¹ (1.University of Colorado Boulder)

キーワード：Venus, Atmosphere, Cloud, Bolide

Perhaps the most recognizable effect of a meteoritic impact on a planet is the eponymous meteor crater. However, impactors can also generate effects within a planetary atmosphere while not leaving behind a crater. Some historical examples include Tunguska on Earth in 1908, and Shoemaker-Levy 9 on Jupiter in 1999. A Bolide, or an airburst impactor, typically breaks apart explosively in response to growing ram pressure as it encounters increasing atmospheric density prior to reaching the surface. In such cases, large fragments may still impact the surface, but a significant fraction of the impactor mass is transformed into meteoritic dust in the atmosphere of the target planet. This deposited dust cloud can serve as a population of cloud condensation nuclei (CCN) for newly formed cloud droplets if the impact occurs in an atmosphere that is fairly moist. We explore this phenomenon by simulating an injection of meteoritic CCN -- estimated from current meteor fragmentation models -- into a planetary atmosphere. We then investigate the effects on the cloud microphysics using the PlanetCARMA model of aerosols and radiative transfer for atmospheres. Specifically, we shall predict what observable consequences might be seen in the clouds of Venus in response to the explosion of a Bolide in the upper atmosphere.