SPECTRUM OF IC-2149 AND ITS CENTRAL STAR

Although the asymmetric optical image of IC 2149 does not fall into an y standard morphologies (Balick et al. 1993), the overall shape and it s radio frequency image show a bilateral symmetry. The central star of spectral class O7.5 is a remarkable object with a rich spectrum showi ng many Fe ions. We discuss this spectrum in detail. The nebula has be en studied utilizing our theoretical photoionization models. Detailed analyses of spectral data are done in both the UV region (lambda < 300 0 angstrom; IUE) and the optical region (3500 angstrom approximately 1 0500 angstrom; the Hamilton Echelle at Lick Observatory). The plasma d iagnostics suggest an electron temperature of 9000 approximately 10,00 0 K and an electron density near 5600 cm-3. Our model calculations wer e carried out with due regard to the above plasma diagnostics. The obs ervations can be interpreted by a model of IC 2149 which consists of t wo components (an equatorial ring and a polar cone), but the total emi ssion is dominated by the relatively denser equatorial shell. Carbon, nitrogen, and oxygen appear to be depleted by a factor of about 3; rat ios of other elements are also lower than in the Sun.