Mid-infrared studies of Carinae-I. Subarcsecond imaging of 12.5 and 17 m

Subarcsecond imaging of η Carinae in the mid-infrared has confirmed that the structure of the homunculus is that of two partially filled, osculating spherical shells. The central star is embedded in hot dusty circumstellar material in close proximity to a complex of cooler, but more massive, small-scale features, probably radiatively heated by the central material. Some of the features have arc-like extensions which are resolved into loop- or ring-like associations of smaller sources. These structures comprise the central core region of η Carinae, of size 5×4 arcsec2, which is otherwise of relatively low density.