New atomic data for the thorium–neodymium stellar chronometer

Abstract

New measurements of the Co I and VI lines blended with the thorium 4019-Å line used in the thorium-neodymium stellar chronometer have been made using a Fourier transform spectrometer. The hyperfine structure of the Co I transitions and the gf value of the V I line have been determined together with high-precision measurements of transition wavelengths. We also report on the hyperfine structure of the CoI line blended with the thorium line at 4086 Å, an alternative to the Th 4019-Å line.