Abstract
Using fast-ion-beam laser-fluorescence spectroscopy (FIBLAS), we have measured the hyperfine structure (hfs) of 14 levels and an additional four transitions in Dy II and the isotope shifts (IS) of 12 transitions in the wavelength range of 422–460 nm. These are the first precision measurements of this kind in Dy II. Along with hfs and IS, new undocumented transitions were discovered within 3 GHz of the targeted transitions. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. Lanthanide abundances are important in diffusion modeling of stellar interiors, and in the mechanisms and history of nucleosynthesis in the universe. Hfs and IS also play an important role in the classification of energy levels, and provide a benchmark for theoretical atomic structure calculations.
Highlights
Accurate elemental abundances in stars and the interstellar medium are essential for understanding stellar formation, evolution, and structure
Even though hfs and isotope shifts (IS) are too small to be resolved in most astrophysical spectra because of Doppler and rotational broadening, they contribute to the overall profile of a spectral line; extracting the elemental abundance from a line often requires a knowledge of the hfs to correct for saturation [1], and ignoring the underlying structure arising from hfs and IS can lead to errors as large as two to three orders of magnitude [2]
The lanthanides are important because they provide a contiguous sequence of observable elements in which patterns of abundance may be observed and related to nucleosynthesis and chemical fractionation [4]
Summary
Accurate elemental abundances in stars and the interstellar medium are essential for understanding stellar formation, evolution, and structure. Atoms 2017, 5, 5 formed from the debris of the very first generation of initially metal-free massive stars (Population III) These studies shed light on the earliest nucleosynthesis of heavy elements in the universe and how they were incorporated into later stars [8,9]. One of the most exciting recent developments in stellar astrophysics has been the rapid expansion of the field of asteroseismology [11], in which the observation of natural, resonant oscillations provides information about stellar interiors and evolution These observations can be photometric or velocity measurements from Doppler shifts. In the latter case, it is essential to be able to model spectral line shapes accurately, requiring good atomic data. The only previous report of hfs is by Murakawa and Kamei [21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
