3 Puppis : a peculiar object with infrared excess.

Abstract

We present a model that accounts for the UV, photographic, and IR observations of 3 Puppis. The model consists of a binary system in which the primary is an A supergiant with a mild chromosphere; the primary fills its Roche lobe. The velocity law in the extended atmosphere, which is responsible for the density distribution of the gas, and a chromospheric rise in temperature explain the H-alpha line profile and the UV spectrum, as well as the IR excess, as being due to free-free and free-bound emission. This result has implications for the modeling of early-type emission-line stars because it enhances the role of the region at the base of the stellar wind, particularly when account is taken of continuum IR emission.