Grain Charging in H II Regions
Equilibrium grain potentials have been calculated as a function of radial position and for a wide range of electron densities in H II regions ionized by stars of spectral type O5 and B0. Results are presented for both graphite (low yield photoemitter) and aluminium oxide (high yield photoemitter) for which laboratory photoemission data has been obtained. The results for aluminium oxide should approximate the behaviour expected of dielectric grains — e.g., silicates which may be present in H II regions. The importance of charging is discussed in relation to the growth and motion of grains in these regions.
KeywordsRadiation Pressure Spectral Type Dust Absorption Central Star Stellar Parameter
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