Determination of hyperfine-induced transition rates from observations of a planetary nebula

Research output: Contribution to journalArticle


Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p P-3(0)o-->2s(2) S-1(0) in the berylliumlike emission line spectrum of N IV at 1487.89 Angstrom. A nebular model allows us to confirm a transition rate of 4x10(-4) sec(-1)+/-33% for this line. The measurement represents the first independent confirmation of the transition rate of hyperfine-induced lines in low ionization stages, and it provides support for the techniques used to compute these transitions for the determination of very low densities and isotope ratios.


  • Tomas Brage
  • PG Judge
  • CR Proffitt
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Condensed Matter Physics
Original languageEnglish
JournalPhysical Review Letters
Issue number28
Publication statusPublished - 2002
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Mathematical Physics (Faculty of Science) (011040001), Physics, science (011013100)