Corotating Interaction Regions and clumping
نویسنده
چکیده
Discrete Absorption Components (DACs) seen in ultraviolet lines are one of the clearest indicators of large-scale structure in the winds of hot stars. Cranmer & Owocki (1996) attributed these DACs to Corotating Interaction Regions (CIRs) which are formed when slow and fast streams collide in the wind. In their model, CIRs are produced by introducing a spot on the stellar surface. The spot can literally be a spot, but can also simulate the effect of non-radial pulsations, or a magnetic field. In the present work, we attempt a quantitative fit to the DACs seen in the Si iv λ 1395 line of the B0.5 Ia star HD 64760. This paper describes the hydrodynamical models used for this fit and discusses the problems in fitting the rotational modulations, which are an additional feature seen in the P Cygni profiles of this star. In a companion paper (Lobel 2007), the radiative transfer code and the fitting of the observed DACs is discussed.
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