Ionization Structure in Equatorial Winds of B[e] Supergiants

Abstract

The non-spherically symmetric winds of B[e] supergiants are investigated. An empirical density distribution is chosen that accounts for the density concentrations and ratios derived from observations, and our model winds are assumed to contain only H and He. We calculate the Strömgren radii and the more accurate ionization fractions for H and He and find that in equatorial direction the winds of B[e] supergiants can become neutral very near the stellar surface. A neutral disk therefore exists around these stars in which molecules and dust can form which are shielded from the photodissociating stellar radiation field.