In-situ Observation of Cosmic Dust Formation toward Micgrogravity Experiment(<Special Issue>Crystal Growth in Space part 2)

Abstract

There are numerous amounts of nanoparticles, which have been called cosmic dust, in universe. Since cosmic dust is a building block of planetary system and works as a substrate for molecular formation, the estimation of their characters such as the composition, size and number density is very important subject in the field of planetary and astronomical sciences. Cosmic dust forms via homogeneous nucleation from ejecta gas of a dying star. To understand the formation condition, nucleation theory and homogeneous nucleation experiment is required. Recent our experiment under gravity indicated that semi-phenomenological nucleation theory is able to explain a result of homogeneous nucleation experiment. We expect that a gas evaporation experiment under microgravity will give a chance to reproduce wider formation condition and better view of formation process of cosmic dust. In addition to the microgravity experiment, we are taking account of characteristic physical properties of nanoparticles to the cosmic dust, because the size of cosmic dust is nanometer scale. Here, we will show our recent results of direct observation of homogeneous nucleation in vapor phase.