2024-03-29T11:56:47Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/865612022-11-17T02:08:08Zhdl_2115_20056hdl_2115_147Inefficient Growth of SiOx Grains : Implications for Circumstellar OutflowsKimura, YukiTanaka, Kyoko K.Inatomi, YukoFerguson, Frank T.Nuth, Joseph A III.Circumstellar dust440To explain observations of abundant circumstellar dust and high stellar wind velocity, most models simply postulate the efficient nucleation and growth of silicate dust particles. Here, we report measurement of the SiO-(SiOx)(n) grain sticking coefficient in a microgravity sounding rocket experiment, indicating very inefficient (0.005-0.016) grain formation from the vapor. Application of this measurement to radiative-driven winds in oxygen-rich asymptotic giant branch stars indicates that the initial grain condensate population should consist of very tiny dust particles in very large numbers. Aggregation of this dust population will produce low-dimension fractal aggregates that should couple well to the stellar radiation field and efficiently drive stellar mass loss.IOP PublishingJournal Articlehttp://hdl.handle.net/2115/865612041-8205The Astrophysical journal letters9341L102022-07-22enginfo:doi/10.3847/2041-8213/ac8002none