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44 CHAPTER 3: An ISO and IUE study of Planetary Nebula NGC 2440Table 3.7–. Ionic and element abundances.Ion λ (nm) Ω ⋆ N ion /N p ICF 1 N el. /N pHe + 587.7 0.0554 ♯He ++ 468.6 0.0639 ♯ 1 0.119C + 232.7 a 1.06(-4)C ++ 190.9 b 5.68(-4)C 3+ 154.9 b 3.75(-5) 1.01 7.19(-4)N 0 519.8, 520.0 b 7.88(-6)N + 658.3 c 1.14(-5)N + 658.3 † c 7.80(-6)N + 575.5 c 8.21(-5)N ++ 175.0 a 3.09(-4)N 3+ 148.5 b 9.39(-5)N 4+ 123.9 b 1.50(-5) 1 4.37(-4)O 0 630.0 b 2.01(-5)O + 372.7, 373.0 d 3.54(-5)O ++ 500.8, 436.3 c 1.82(-4)O 3+ 25 900 e 1.06(-4) 1.1 3.78(-4)Ne + 12 810 f 1.10(-5)Ne ++ 15 500 g 4.10(-5)Ne 3+ 242.5,472.5 h,b 2.26(-5)Ne 4+ 14 320 c 8.99(-6)Ne 4+ 24 300 c 1.65(-5)Ne 5+ 7650 e 1.02(-5) 1 1.10(-4)Mg + 280.0 i 7.56(-x9)Mg 4+ 5610 j 3.42(-6) – –S + 671.6, 673.1 k 3.24(-7)S ++ 18 710 l 1.80(-6)S 3+ 10 510 m 1.10(-6) 1.47 4.72(-6)Cl ++ 553.8, 551.8 b 4.51(-8)Ar + 6980 n 3.58(-7)Ar ++ 8990 l 1.31(-6)Ar 3+ 471.1, 474.0 o 7.09(-7)Ar 4+ 7900, 700.6 l 2.38(-7)Ar 5+ 4527 p 3.58(-7) 1.07 3.17(-6)1 ICF = Ionization Correction Factor.♯ Using the predictions for the helium emission lines given by Benjamin et al. (1999).† Value from Perinotto & Corradi (1998).⋆ References for the collisional strengths (Ω): a) Blum & Pradhan (1992), b)Mendoza (1983),c) Lennon & Burke (1994), d) McLaughlin & Bell (1993), e) Zhang et al. (1994), f) Saraph& Tully (1994), g) McLaughlin & Bell (2000), h) Ramsbottom et al. (1998), i) Sigut &Pradhan (1995), j) Butler & Zeippen (1994), k) Keenan et al. (1996), l) Galavis et al. (1995),m) Saraph & Storey (1999), n) Pelan & Berrington (1995), o) Ramsbottom et al. (1997), p)Saraph & Storey (1996).
3.6. Chemical abundances 45Table 3.8–. Comparison of abundances in NGC 2440.Element Present Sun 1 O,B Stars 2 Hyung & Aller 3 Kwitter 4 Perinotto 5abund. ICF-M Model Model & CorradiHelium 0.119 0.098 0.126 0.11 0.12 0.124Carbon 7.2(-4) 3.5(-4) 1.7(-4) 3.4(-4) 4.0(-4) 6.3(-4)Nitrogen 4.4(-4) 9.3(-5) 6.5(-5) 1.0(-3) 9.0(-4) 8.2(-4) 7.0(-4)Oxygen 3.8(-4) 7.4(-4) 4.2(-4) 4.4(-4) 3.5(-4) 5.7(-4) 3.8(-4)Neon 1.1(-4) 1.2(-4) 1.2(-4) 9.5(-5) 7.0(-5) 7.4(-5) 6.0(-5)Magnesium – 3.8(-5) 2.4(-5) 2.0(-6) 2.0(-6)Silicon – 3.5(-5) 2.4(-5) 1.7(-6) 1.9(-6)Sulfur 4.7(-6) 1.9(-5) 1.2(-5) 1.7(-6) 2.0(-6) 3.1(-6)Chlorine – 1.9(-7) 1.9(-7) 1.3(-7) 1.2(-7)Argon 3.2(-6) 3.6(-6) 2.0(-6) 2.2(-6) 2.6(-6)1 Solar abundance from Grevesse & Noels (1993) and Anders & Grevesse (1989).2 O, B star abundances are the average of Gies & Lambert (1992) and Kilian-Montenbrucket al. (1994).3 Abundances by Hyung & Aller (1998), determined using the ICF–Method and modeling.4 From Kwitter & Henry (1996).5 From Perinotto & Corradi (1998).of neon ions (with varying IP) as an example.3.6.2 Discussion of the abundancesThe abundances derived have been compared to those found in the Sun, O, B stars and previousliterature (see Table 3.8 for references).The helium and carbon abundances agree with those found by Kwitter & Henry (1996).The carbon abundance found by Hyung & Aller (1998) seems too small. The nitrogen is halfthat found by the same authors. The ICF used by Hyung & Aller (1998) seems too large. Onthe other hand the oxygen and neon abundances agree quite well. The sulfur abundance ishigher than the ICF–Method and Model employed by Hyung & Aller (1998), but four andthree times smaller than that of the Sun and O, B stars. For this element a high ICF of 1.47(see Table 3.7) was needed because contribution from S 4+ and S 5+ is expected. The IP ofthese ions (47.3 and 72.7 eV respectively) is still in the limit where the radiation of the centralstar can ionize them. The reason for the lower abundance of sulfur is not clear. It can not bedue to the ICF used because to match the solar sulfur abundance an ICF of 5.8 (or ICF=2.6to match the O, B stars) should be used which is definitively too high. Finally the argonabundance from Hyung & Aller (1998) is smaller than the present study. The abundancesin Perinotto & Corradi (1998) constitute an average of various regions of the nebula. Sincethey have been weighted to the local surface brightness, they refer to the brightest positionswhich correspond to the center, p1 and n1 (Sect. 3.4.3 or see Perinotto & Corradi (1998) fordetails) and are therefore comparable to ISO and IUE observations. The helium, oxygen,
Page 1 and 2: RIJKSUNIVERSITEIT GRONINGENPhysics
Page 3 and 4: To my parents
Page 5 and 6: Contents1 Introduction 11.1 Evoluti
Page 7 and 8: CONTENTSvii5 Probing AGB nucleosynt
Page 9 and 10: 1IntroductionPLANETARY NEBULAE are
Page 11 and 12: 1.1. Evolution of low and intermedi
Page 13 and 14: 1.2. Planetary Nebulae 5Flash−Dri
Page 15 and 16: 1.3. Physics in PNe 7their whole li
Page 17 and 18: 1.3. Physics in PNe 95.35 eVO IIIλ
Page 19 and 20: 1.4. Studying PNe in the infrared 1
Page 21 and 22: 2The ISO-SWS Spectrum ofPlanetary N
Page 23 and 24: 2.3. Data reduction 15Table 2.1-. C
Page 25 and 26: 2.4. Line flux discussion 17Table 2
Page 27 and 28: 2.5. The visual and the ultraviolet
Page 29: 2.6. Analysis 21Table 2.5-. Electro
Page 32 and 33: 24 CHAPTER 2: The ISO-SWS Spectrum
Page 39 and 40: 3An ISO and IUE study of PlanetaryN
Page 41 and 42: 3.3. Corrections to line fluxes 33[
Page 43 and 44: 3.4. Line fluxes 35Table 3.1-. Comp
Page 45 and 46: Table 3.3-. IUE intensities, fluxes
Page 47 and 48: 3.5. Physical parameters 393.4.3 Op
Page 49 and 50: 3.5. Physical parameters 41Table 3.
Page 51: 3.6. Chemical abundances 43Table 3.
Page 55: 3.7. Conclusions 47Acknowledgements
Page 58 and 59: 50 CHAPTER 4: Abundances of Planeta
Page 77 and 78: 5Probing AGB nucleosynthesis viaacc
Page 79 and 80: 5.1. Introduction 71about the synth
Page 81 and 82: Table 5.2-. Radius, Zanstra tempera
Page 83 and 84: 5.3. Accurate abundances of ISO-obs
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Page 87 and 88: 5.4. Nucleosynthesis in low- and in
Page 89 and 90: 5.5. Synthetic TP-AGB calculations
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5.6. Comparison between models and
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5.7. Summary and conclusions 103Fig
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5.7. Summary and conclusions 105A s
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6Physical Conditions in PDRs around
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6.2. Observations 109are not promin
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6.4. General parameters of the PNe
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6.4. General parameters of the PNe
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Table 6.3-. Radius, Zanstra tempera
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6.6. Lines fluxes 117Figure 6.2-. S
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6.7. Physical conditions of the PDR
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6.8. PDRs versus Shocks 127Figure 6
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6.10. Atomic, ionized and molecular
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6.10. Atomic, ionized and molecular
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6.11. General discussion 133Table 6
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6.11. General discussion 135Figure
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6.12. Summary and Conclusions 137su
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7Conclusions and future workTHE res
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141• PNe with He/H > 0.14. The st
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143HERSCHEL The launch of this sate
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Nederlandse SamenvattingSTERREN wor
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Nederlandse Samenvatting 147Figuur
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Nederlandse Samenvatting 149PHOTOIO
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Nederlandse Samenvatting 151Figuur
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Nederlandse Samenvatting 153infraro
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English SummarySTARS are born, live
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English Summary 157Figure 2-. Two e
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English Summary 159PHOTOIONIZATIONR
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English Summary 161Figure 5-. Spect
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English Summary 163all) stages of i
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BibliographyAcker A., Marcout J., O
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BIBLIOGRAPHY 167Henry R.B.C., Kwitt
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BIBLIOGRAPHY 169Pottasch S.R., Bern
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List of PublicationsPublications in
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AcknowledgementsI could easily writ
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Acknowledgements 175sense of humor,
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