Submillimetre Variability of Eta Carinae: cool dust within the outer
  ejecta
  Previous submillimetre (submm) observations detected 0.7 solar masses of cool
dust emission around the Luminous Blue Variable (LBV) star Eta Carinae. These
observations were hindered by the low declination of Eta Carinae and
contamination from free-free emission orginating from the stellar wind. Here,
we present deep submm observations with LABOCA at 870um, taken shortly after a
maximum in the 5.5-yr 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 ionised emission features suggests the 870um is dominated by
emission from the ionised wind and not thermal emission from dust. We estimate
0.4 +/- 0.1 solar masses of dust surrounding Eta 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 Eta Carinae has ejected >
40 solar masses of gas within this timescale.
