IRS observations of the LMC planetary nebula SMP83
  The first observations of the infrared spectrum of the LMC planetary nebula SMP83 as observed by the recently launched Spitzer Space Telescope are presented. The high resolution R~600 spectrum shows strong emission lines but no significant continuum. The infrared fine structure lines are used, together with published optical spectra, to derive the electron temperature of the ionized gas for several ions. A correlation between the electron temperature with ionization potential is found. Ionic abundances for the observed infrared ions have been derived and the total neon and sulfur abundances have been determined. These abundances are compared to average LMC abundances of HII regions to better understand the chemical evolution of these elements. The nature of the progenitor star is also discussed. 
J. Bernard-Salas (1), J.R. Houck (1), P.W. Morris (2), G.C. Sloan (1),   S.R. Pottasch (3), D.J. Barry (1), ((1) Cornell Uni...