SIMBAD references

Lifetimes on the sub-nanosecond scale for the levels v²D_3/2, v²F_3/2 and v²F_5/2 in the 4d5s5p configuration in ZrII have been measured, using the method of laser-induced fluorescence. Combined with branching fractions obtained with the Lund Ultraviolet (UV) Fourier Transform Spectrometer (FTS), experimental oscillator strengths have been derived. From Hubble Space Telescope/Goddard High-Resolution Spectrograph spectra, the zirconium abundance in the HgMn star χ Lupi has been determined from ZrII and ZrIII lines. More than an order of magnitude difference in the ZrII abundance has been derived from these ionization stages. The difference is much too large to be explained by uncertainties in the oscillator strengths. Possible explanations of this difference have to be found in the stellar models, such as the influence of non-LTE or diffusion.