Ground-based spectroscopy of η Car shows periodic changes in some emission-line wavelengths. These variations have been cited as strong evidence that this object is a 5.5 yr binary system and have been used to produce specific orbit models. High spatial resolution data obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, however, do not confirm the predicted velocity behavior; therefore, the published orbit models are almost certainly invalid. Wavelength fluctuations seen at ground-based spatial resolution most likely result from other effects, which we describe. If this object is a binary system (which has not been proven), then the parameters of the secondary star and of the orbit remain largely unknown.
Bibliographical noteFunding Information:
1 Based on observations with the NASA/ESA Hubble Space Telescope. Our observations and data reduction were supported by grant number GO-7302 from the Space Telescope Science Institute and also by NASA funding to the STIS Science Team. The HST is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
- Stars: individual (η Carinae)