HST/GHRS observations of the compact slow ejecta of eta Carinae

We report spectroscopic observations of eta Car and adjacent gas with an unprecedented combination of spatial and spectral resolution, 0.1 '' X0.1 Angstrom. Radial velocities show that the bright objects C and D, 0.2 '' from the star, are slow equatorial ejecta. The narrow emission lines which fluctuate in the spectrum of the core region are found to originate in C, D, and related gas. Our data and earlier speckle observations suggest that either C and D were formed long after the Great Eruption of eta Car had ceased, or else they have been continuously accelerated outward since they were ejected. These strange objects are essential components of the equatorial-debris puzzle, which is crucial regarding the nature of this star and its instability. Moreover, the observed bright narrow emission lines in CD are excited by peculiar mechanisms that deserve more attention. (C) 1997 American Astronomical Society.