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Lego Figure holding a lego telescope. Photo

Henrik Hartman

Researcher (Leave of Absence)

Lego Figure holding a lego telescope. Photo

New forbidden and fluorescence Fe III lines identified in HST spectra of eta Carinae


  • Sveneric Johansson
  • T Zethson
  • Henrik Hartman
  • J-O Ekberg
  • K Ishibashi
  • K Davidson
  • T Gull

Summary, in English

We discuss the origin of eight emission lines in the spectra of gas blobs close to the central star of eta Carinae. The spectra have been obtained with the Goddard High Resolution Spectrograph (GHRS) and the Space Telescope Imaging Spectrograph (STIS) onboard the Hubble Space Telescope. Between 2400 and 2500 Å five narrow lines are identified as new forbidden lines of doubly ionized iron, [Fe III]. We present gA-value data for the corresponding transitions, which combine two different metastable configurations of Fe III. An anomalous intensity of the narrow Fe III line (UV 34) at 1914 Å is explained as fluorescence due to HLyalpha pumping. A level mixing of about 1% increases the f-value of the pumped excitation channel by more than two orders of magnitude, which makes the pumping efficient and the fluorescence significant. We introduce a new designation for fluorescence lines photoexcited by an accidental resonance, eg. < Fe III> in the case of doubly ionized iron. Based on observations with the NASA/ESA Hubble Space Telescope, and supported by grant numbers GO-6501 and GO-7302 from the Space Telescope Science Institute. The STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.


  • Lund Observatory - Has been reorganised

Publishing year







Astronomy and Astrophysics



Document type

Journal article


EDP Sciences


  • Astronomy, Astrophysics and Cosmology



Research group

  • Atomic Astrophysics


  • ISSN: 1432-0746