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T. R. Gull (NASA/GSFC/LASP), K. Davidson, K. Ishibashi (U MN), HST Cycle 7 STIS Eta Carinae Team
First observations of Eta Carina with the Space Telescope Imaging Spectrograph have been accomplished using a 52x0.1 arcsec aperture and a resolving power of 5,000 to 10,000 from 1640A to 10400A. The spatially-resolved spectra indicated a well-defined point source for component A down to 4000A. Scattered starlight is detected to the outer reaches of the Homunculus at longer wavelengths and in the brighter P-Cygni lines. With decreasing wavelength, the scattered light structure closes in around Eta Carina as would be expected. Shortward of 4000A, various line absorptions inceasingly obscure the direct view of component A, but the modified stellar spectrum is easily detected by scattered light on bright surfaces such as Welgelt's components B,C, and D in the immediate vicinity. Faint stellar emission resumes below 2100A, but with very noticable nearby scattered light down to 1640A, where the CCD detector observations cease.
Several nebular features are observed: background H alpha and [NII] external to the Homunculus, the reflected spectrum of Eta Carina, especially in the P-Cygni-shaped Balmer lines, nebular Balmer line absorption, scattered starlight very close to the star, a bright, ionized region within two arcsec radius of Eta Carina and a very small, but bright FeII emission nebula within 0.25 arcsec of component A.
Followup observations are in planning stage for repeating the observations during the higher excitation phase of Eta Carina.
The author(s) of this abstract have provided an email address for comments about the abstract: gull@sea.gsfc.nasa.gov