thesis - IRS, The Infrared Spectrograph
thesis - IRS, The Infrared Spectrograph
thesis - IRS, The Infrared Spectrograph
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CONTENTSvii5 Probing AGB nucleosyn<strong>thesis</strong> via accurate Planetary Nebula abundances 695.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705.2 Sample of PNe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725.2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725.2.2 HR diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745.3 Accurate abundances of ISO-observed PNe . . . . . . . . . . . . . . . . . 755.3.1 Abundances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755.3.2 Comparison with Solar abundances . . . . . . . . . . . . . . . . . 785.4 Nucleosyn<strong>thesis</strong> in low- and intermediate-mass stars . . . . . . . . . . . . 795.5 Synthetic TP-AGB calculations . . . . . . . . . . . . . . . . . . . . . . . 795.5.1 Nucleosyn<strong>thesis</strong> and mixing assumptions of the TP-AGB model . . 815.6 Comparison between models and observations . . . . . . . . . . . . . . . 835.6.1 <strong>The</strong> starting point: TP-AGB models with solar-scaled molecularopacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 835.6.2 Sub-grouping of the ISO sample and comparison with other PNe data 835.6.3 PNe with “normal” He abundances . . . . . . . . . . . . . . . . . 865.6.4 PNe with extremely high He abundance . . . . . . . . . . . . . . . 925.7 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 1036 Physical Conditions in PDRs around Planetary Nebulae 1076.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1096.3 Reduction techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.4 General parameters of the PNe . . . . . . . . . . . . . . . . . . . . . . . 1116.4.1 HR diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1136.5 <strong>The</strong> SWS and LWS spectra . . . . . . . . . . . . . . . . . . . . . . . . . 1146.6 Lines fluxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1166.6.1 Analysis of the atomic lines . . . . . . . . . . . . . . . . . . . . . 1166.6.2 Background contamination and aperture corrections . . . . . . . . 1166.7 Physical conditions of the PDRs . . . . . . . . . . . . . . . . . . . . . . . 1196.7.1 G 0 and the FIR flux . . . . . . . . . . . . . . . . . . . . . . . . . 1196.7.2 Comparison with PDR models . . . . . . . . . . . . . . . . . . . 1216.8 PDRs versus Shocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1266.9 H 2 in NGC 7027, Hb 5 and NGC 6302 . . . . . . . . . . . . . . . . . . . . 1286.9.1 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1286.9.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1286.10 Atomic, ionized and molecular mass . . . . . . . . . . . . . . . . . . . . 1296.11 General discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1326.12 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 1377 Conclusions and future work 139Nederlandse Samenvatting 145English Summary 155List of Publications 171