Eta Carinae: The iron curtain lifts!

Observations of Eta Carinae and the surrounding ejecta nebulae were done with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) during the past two years using a $52″×0.1″$ aperture and gratings with $R≈4000–8000.$ In March 1998 and February 1999 complete coverage of the spectrum from 1640 Å to 10400 Å was accomplished at the same position angle. Not only did Eta Carinae brighten in that interval by 60 percent, but also the nebulosities within the central two arcseconds changed considerably. Most notable is the overall decrease in [Fe II] emissions and Fe II absorptions with increases in doubly-ionized ionic emissions including [Fe III]. At this time, we do not know if the changes are due to a 5.5 year cyclic variation or an overall brightening of Eta Carinae. Continued monitoring with STIS is planned for the near future and proposals are submitted for the full 5.5 year spectroscopic cycle.