[Previous] | [Session 50] | [Next]
C.R. Cowley (U. Michigan), F. Kupka (Institute for Astronomy, Vienna), G. Mathys (ESO)
Przybylski's star (HD 101065) may be the most heavily blanketed star known. It therefore provides a test of our techniques for line blanketing. The current abstract draws on a paper in preparation by CRC, T. Ryabchikova, F. Kupka, G. Mathys, and D. J. Bord, based on ESO spectra obtained by GM. Unfortunately, the atomic species that provide the majority of the line blanketing in Przybylski's star does not have enough atomic data for realistic calculations of the blanketing. We therefore discuss three models in which iron-group elements were articifically elevated in abundance in the calculation of opacity used to construct the models. We thank Drs. R. L. Kurucz, and Bengt Edvardsson for calculating respectively Models 1 (dashed [Fe/H]=+3) and 2 (dot-dash, [Fe/H]=+2) at our request. Model 3 (line, [Fe/H]) was calculated by FK, using the Canuto-Mazzitelli formalism. Figure 1 (www.astro.lsa.umich.edu/usrs/cowley/models.gif), shows these 3 models in good agreement with one another, and clearly different from a standard solar-abundance Atlas9 model (dashed) with the same effective temperature. All three models are scaled to Te=6600K. The blanketed models have little or no convection, and show the lowered boundary temperature of classical picket-fence models. The true boundary temperature may be still lower than in these numerical models. Abundances from Pr I and Nd I are systematically higher than those from the corresponding second spectra, as are those from Pr III and Nd III. It was noted long ago by Przybylski and others that the Balmer profiles had cores indicative of temperatures of some 6000K; the wings could be fit with much higher temperatures--perhaps as high as 7500K. Molecular species have been sought but not identified. Calculations show CN and CH lines would be very weak, even if the temperature between log(tau5000)=-3.5 and -5.4 were allowed to drop to 3000K.
If you would like more information about this abstract, please follow the link to www.astro.lsa.umich.edu/usrs/cowley/models.gif. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
The author(s) of this abstract have provided an email address for comments about the abstract: cowley@umich.edu
