The increase in radio emission has occurred because cool gas close to the star, which in 1992 did not show up in the radio images, has been excited by a blast of radiation which we have not yet identified. We can see how this excited gas is distributed in the high resolution radio maps shown in the fourth image. In this image the left panels represent the actual emission at the epoch noted at the top of each panel, while the right hand panels show the change in the radio emission since the previous epoch.
Eta Carinae is in the southern constellation of Carina, where we look along one of the spiral arms which make up our Galaxy. The beautiful Carina nebula is shown in the "Miscellaneous" section of the Image Gallery.
All these images of Eta Carinae were made with the Australia Telescope , a radiotelescope near Narrabri in north-central New South Wales.