The O IV and S IV intercombination lines in the ultraviolet spectra of astrophysical sources
Författare
Summary, in English
New electron density diagnostic line ratios are presented for the O IV 2s(2)2p P-2-2s2p(24)P and S IV 3s(2)3p P-2-3s3p(24)P intercombination lines around 1400 Angstrom comparison of these with observational data for the symbiotic star RR Telescopii (RR Tel), obtained with the Space Telescope Imaging Spectrograph (STIS), reveals generally very good agreement between theory and observation. However the S IV P-2(3/2)-P-4(1/2) transition at 1423.824 Angstrom is found to be blended with an unknown feature at 1423.774 Angstrom. The linewidth for the latter indicates that the feature arises from a species with a large ionization potential. In addition, the S IV P-2(1/2)-P-4(3/2) transition at 1398.044 Angstrom is identified for the first time (to our knowledge) in an astrophysical source other than the Sun, and an improved wavelength of 1397.166 Angstrom is measured for the O IV P-2(1/2)-P-4(3/2) line. The O IV and S IV line ratios in a sunspot plume spectrum, obtained with the Solar Ultraviolet Measurements of the Emitted Radiation (SUMER) instrument on the Solar and Heliospheric Observatory, are found to be consistent, and remove discrepancies noted in previous comparisons of these two ions.
Avdelning/ar
Publiceringsår
2002
Språk
Engelska
Sidor
901-909
Publikation/Tidskrift/Serie
Monthly Notices of the Royal Astronomical Society
Volym
337
Issue
3
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Oxford University Press
Ämne
- Condensed Matter Physics
Nyckelord
- binaries : symbiotic
- atomic data
- Sun : UV radiation
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1365-2966