Sr II and [Sr II] Emission in the Ejecta of η Carinae

Abstract

We have discovered four extremely surprising emission lines of strontium in ejecta near η Carinae. Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations made in 1999 show two narrow features whose wavelengths correspond to the forbidden transitions of Sr II, and we have found no other plausible identification for these lines. The identifications are confirmed by new HST/STIS observations of the same stellar position, in which the Sr II resonance lines are observed. Moreover, [Ti II], [Ni II], [Mn II], and [Co II] lines are unusually strong relative to [Fe II] at the same position. Based on observations made with the NASA/ESA Hubble Space Telescope and supported by STIS IDT GTO 8036 and grant GO 8327 from the Space Telescope Science Institute. The STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.