1997A&A...321L..21V

We present mid-infrared imaging of the LBV HR Car and its surrounding nebula. The 10µm broad-band N image reveals a geometry which is not point symmetric with respect to the central star on an arcsecond scale. The 12.8µm narrow-band [NeII] image shows a clumpy structure which does not follow the N-band distribution. In addition, we detect a faint and probably clumpy outer nebula about 15" across. The morphology of the infrared nebula and in particular its asymmetry is not at all in agreement with the large-scale structures as seen in optical images. Three different episodes of shell ejection can now be distinguished for HR Car: the arc-like structures seen in the optical, about 35" across, the faint IR nebula seen in the N-band, about 15" across, and the small, irregular nebula less than 8" across. The main conclusion we draw from this is that the geometry of mass-ejections in HR Car is highly time-dependent and that multiple shell ejections can occur in LBVs. The distance of the small IR nebula from the central star can be well explained by a dust shell that is composed of silicates and is in radiative equilibrium with the central star.