thesis - IRS, The Infrared Spectrograph

4Abundances of Planetary NebulaeBD+30 3639 and NGC 6543Based on:J. Bernard-Salas, S.R. Pottasch, P.R. Wesselius, & W.A. FeibelmanASTRONOMY & ASTROPHYSICS, 406, 165 (2003)INFRARED spectra taken with the Short Wavelength Spectrometer on board ISO and UVobservations with IUE of planetary nebulae BD+30 3639 and NGC 6543 are presented.The extinction derived using infrared lines for BD+30 3639 is E B−V = 0.34, slightly higherthan previous determinations. For NGC 6543 the extinction found from the hydrogen linesis E B−V = 0.07. Infrared, optical and ultraviolet data have been used to derive the physicalparameters of the nebula. BD+30 3639 has an average T e = 8500 K and N e = 11 000 cm −3 . Inthe case of NGC 6543 a T e = 8200 K and N e = 5000 cm −3 have been found, in agreement withprevious determinations. The element abundances have been derived and compared to thosefound in the Sun and O, B stars. This comparison gives a hint of the mass of the progenitorstars from which they evolved.