Advanced

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

Johansson, Sveneric LU ; Zethson, T; Hartman, Henrik LU ; Ekberg, J-O; Ishibashi, K; Davidson, K and Gull, T (2001) In Astronomy and Astrophysics 361. p.977-977
Abstract
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Astronomy and Astrophysics
volume
361
pages
977 - 977
publisher
EDP Sciences
ISSN
1432-0746
language
English
LU publication?
yes
id
962d6223-41a5-45aa-841e-2850f997bdb9 (old id 940080)
date added to LUP
2008-01-21 10:36:40
date last changed
2016-04-16 12:38:17
@article{962d6223-41a5-45aa-841e-2850f997bdb9,
  abstract     = {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. &lt; Fe III&gt; 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.},
  author       = {Johansson, Sveneric and Zethson, T and Hartman, Henrik and Ekberg, J-O and Ishibashi, K and Davidson, K and Gull, T},
  issn         = {1432-0746},
  language     = {eng},
  pages        = {977--977},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {New forbidden and fluorescence Fe III lines identified in HST spectra of eta Carinae},
  volume       = {361},
  year         = {2001},
}