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D.J. Bord (UMD), C.R. Cowley (UM), T.A. Ryabchikova (IA,RuAS), G. Mathys (ESO)
HD 101065 ("Przybylski's star") is a rapidly oscillating Ap star with a weak magnetic field and complex spectrum dominated by lines of rare-earth elements (REE).
We have employed a spectrum of HD 101065 from the ESO 3.5m New Technology Telescope and the ESO Multi-Mode Instrument. The spectrum has a resolving power of 80,000 from \lambda\lambda3960 - 6632. The S/N ratio of the reduced spectrum is approximately 200 at the blue (faintest) end. We analyzed the spectra using programs developed independently at Michigan and Moscow.
Abundances were obtained for 35 neutral and ionized species, with particular care given to Fe I, Fe II, Nd II, Nd III, Pr II, and Pr III. The model is still not very closely determined. We adopted T\rm e = 7500K, log(g) = 3.5, and v\rm turb = 1.0km/s, which must still be considered preliminary. The temperature remains uncertain by several hundred degrees. For the adopted parameters, we find [Fe/H] \approx -0.45 dex and [RE/H] \approx +3.7 dex. Abundances derived from Nd II and Nd III differ by \geq 0.65 dex, while those from Pr II and Pr III differ by \geq 1.2 dex. The doubly ionized species give higher abundances. Small differences in the broadening parameters due to hyperfine structure or the Zeeman effect could reconcile these results, since the lines are mostly on the flat part of their curves of growth. Similar differences have been found for other roAp stars. Details of our analysis, as well as critical comparisons of our results with those of prior studies, will be presented.
Our work confirms the assertion made long ago by Wegner, Petford, Kurtz, and their coworkers that the unique appearance of the spectrum of this star is due primarily to the great strength of lanthanide spectra, and not to a virtual absence of iron-group lines.
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The author(s) of this abstract have provided an email address for comments about the abstract: cowley@umich.edu