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K. Ishibashi (Univ. of Minnesota), K. Davidson (Univ. of Minnesota), T. R. Gull (NASA/GSFC/LASP), HST Cycle 7 GO Eta Carinae Team
Our HST/STIS imaging spectroscopic observations in March 1998 reveal two unexplained velocity structures moving in a polar direction within 2 seconds of arc (~ 5\times{103} A.U.) of the massive star \eta Carinae. One of the two flows shows a trace of ``bipolar'' plasma flow which resembles fast moving ejecta (~300 km/s) being slowed down by the existing circumstellar medium, while the other component illustrates ubiquitous, very slow moving ejecta of \sim -40 km/s at any position along the slit. Superposition of these two velocity components in the spectroscopic image shows a pattern which resembles an ``inverse-dollar'' sign, i.e., a dollar character `` $'' being flipped along the vertical bar. These velocity structures are quite unexpected and do not fit easily into previous ideas concerning the stellar wind.
The author(s) of this abstract have provided an email address for comments about the abstract: bish@sea.gsfc.nasa.gov