Quantitative Spectroscopy of K 648 --the PNN of Ps1 in the Globular Cluster M15
Dreizler, Stefan; Werner, Klaus; Heber, Ulrich
Germany
Abstract
We report preliminary results of a quantitative study of high resolution UV and optical spectra of K648 obtained with the Hubble Space Telescope and the Calar Alto 3.5 m telescope, respectively. Using state of the art NLTE model- atmospheres we determine atmospheric parameters and the abundances of hydrogen, helium and carbon. K648 is found to be helium- and carbon-rich when compared to solar composition.