Stratification and isotope separation in CP stars

Stratification and isotope separation in CP stars

We investigate the elemental and isotopic stratification in the atmospheres of selected chemically peculiar (CP) stars of the upper main sequence. Reconfiguration of the UV-Visual Echelle Spectrograph in 2004 has made it possible to examine all three lines of the Ca II infrared (IR) triplet. Much of the material analysed was obtained in 2008. We support the claim of Ryabchikova, Kochukhov & Bag...

Isotope Effects, Isotope Separation and Isotope Fractionation

Modelling of mercury isotope separation in CP stellar atmospheres: results and problems

Formation of anomalous isotope abundances in the atmospheres of chemically peculiar (CP) stars can be explained by light-induced drift (LID). This effect is additional to the radiative acceleration and appears due to systematic asymmetry of radiative flux in partly overlapping isotopic spectral line profiles. LID causes levitation of an isotope with a red-shifted spectral line and sinking of an...

Electrochemical isotope effect and lithium isotope separation.

A large electrochemical isotopic effect is observed upon the electrodeposition of lithium from solutions of propylene carbonate producing isotopically light metal deposits. The magnitude of fractionation is controlled by the applied overpotential and is largest close to equilibrium. Calculated partition function ratios for tetrahedrally coordinated lithium complexes and metallic lithium predict...

Heavy calcium in CP stars★

Large wavelength shifts of infrared triplet lines of Ca ii have been observed in the spectra of HgMn and magnetic Ap stars. They have been attributed to the heavy calcium isotopes, including Ca. One member of the triplet, λ8542, had been either unavailable, or of poor quality in earlier spectra. The present material shows conclusively that the stellar λ8542 shifts are consistent with an interpr...