J/ApJS/169/120ivo://CDS.VizieR/J/ApJS/169/120doi:10.26093/cds/vizier.21690120CDSLawler J.E.Den Hartog E.A.Labby Z.E.Sneden C.Cowan J.J.Ivans I.I.2009-10-01T09:10:57Z2009-10-01T09:04:12ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fratomic-physicschemical-abundancesRadiative lifetimes from laser-induced fluorescence measurements, accurate to ~+/-5%, are reported for 41 odd-parity levels of HfII (Z=72). The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of HfII. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for lines in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log{epsilon}(Hf)=0.88+/-0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log{epsilon}(Hf/La)=-0.13+/-0.02 ({sigma}=0.06) and log{epsilon}(Hf/Eu)=+0.04+/-0.02 ({sigma}=0.06). The observed average stellar abundance ratio of Hf/Eu and La/Eu is larger than previous estimates of the solar system r-process-only value, suggesting a somewhat larger contribution from the r-process to the production of Hf and La. The newly determined Hf values could be employed as part of the chronometer pair, Th/Hf, to determine radioactive stellar ages.2007ApJS..169..120Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/169/120CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/377/361 : Fe II transition probabilities and loggf (Pickering+, 2001)J/ApJS/167/292 : Laboratory transition probabilities for Gd IIJ/ApJS/162/227 : Transition probabilities for SmII (Lawler+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/169/120https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/169/120http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/169/120https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/169/120https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/169/120http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/169/120GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJS/169/120/table3Atomic transition probabilities for Hf II organized by increasing wavelength in airrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength in air in Angstroms0.1nmem.wldoubleE1Upper level energycm**-1phys.energy;phys.atmol.leveldoubleJ1Upper level J valuephys.atmol.qnfloatE0Lower level energycm**-1phys.energy;phys.atmol.leveldoubleJ0Lower level J valuephys.atmol.qnfloatATransition probability1e+06s**-1phys.atmol.transProbfloate_ATotal uncertainty in TransP1e+06s**-1stat.errorfloatlog(gf)Log of the degeneracy times the oscillator strengthphys.atmol.oscStrengthfloat