2010A&A...512A..33L

In an attempt to understand the extraordinarily small mass-loss rates of late-type O dwarfs, mass fluxes in the relevant part of (T_eff, g)-space are derived from first principles using a previously-described code for constructing moving reversing layers. From these mass fluxes, a weak-wind domain is identified within which a star's rate of mass loss by a radiatively-driven wind is less than that due to nuclear burning. The five weak-wind stars recently analysed by Marcolino et al. (2009A&A...498..837M) fall within or at the edge of this domain. But although the theoretical mass fluxes for these stars are ≃1.4dex lower than those derived with the formula of Vink et al. (2000A&A...362..295V), the observed rates are still not matched, a failure that may reflect our poor understanding of low-density supersonic outflows. Mass fluxes are also computed for two strong-wind O4 stars analysed by Bouret et al. (2005A&A...438..301B). The predictions agree with the sharply reduced mass loss rates found when Bouret et al. take wind clumping into account.