2010MNRAS.401L..48G

Previous submillimetre (submm) observations detected 0.7M_☉of cool dust emission around the luminous blue variable (LBV) star η Carinae. These observations were hindered by the low declination of η Carinae and contamination from free-free emission originating from the stellar wind. Here, we present deep submm observations with LABOCA at 870µm, taken shortly after a maximum in the 5.5-year radio cycle. We find a significant difference in the submm flux measured here compared with the previous measurement: the first indication of variability at submm wavelengths. A comparison of the submm structures with ionized emission features suggests the 870µm is dominated by emission from the ionized wind and not thermal emission from dust. We estimate of dust surrounding η Carinae. The spatial distribution of the submm emission limits the mass loss to within the last thousand years, and is associated with mass ejected during the great eruptions and the pre-outburst LBV wind phase; we estimate that η Carinae has ejected >40M_☉of gas within this time-scale.