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Magellanic Cloud planetary nebulae as probes of stellar evolution and populations

Magellanic Cloud planetary nebulae as probes of stellar evolution and populations. Letizia Stanghellini. Magellanic Cloud PNe. The known distances, low field reddening, relative proximity, and metallicity range make them Absolute probes of post-AGB evolution

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Magellanic Cloud planetary nebulae as probes of stellar evolution and populations

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  1. Magellanic Cloud planetary nebulae as probes of stellar evolution and populations Letizia Stanghellini Planetary nebulae beyond the Milky Way - May 19-21, 2004

  2. Magellanic Cloud PNe The known distances, low field reddening, relative proximity, and metallicity range make them • Absolute probes of post-AGB evolution • Benchmarks for extragalactic PN populations Planetary nebulae beyond the Milky Way - May 19-21, 2004

  3. Probes of post-AGB evolution • Nebular analysis • Morphology • chemistry • Links to central stars (CSs) • Transition time • Winds Planetary nebulae beyond the Milky Way - May 19-21, 2004

  4. Benchmarks for extragalactic PN populations • PNe and UCHII regions • Luminosity distribution and metallicity • PNe types in the PNLF Planetary nebulae beyond the Milky Way - May 19-21, 2004

  5. PN morphology • Depends on the formation and dynamic evolution of the PN, on the evolution of the central star and of the stellar progenitor, and on the environment. • From Galactic PNe: • Round, Elliptical, Bipolar [includes bipolar core and multipolar], and Point-symmetric • Bipolar PNe are located in the Galactic plane, have high N, He, indication of massive CSs: remnant of 3-8 M stars? Planetary nebulae beyond the Milky Way - May 19-21, 2004

  6. Round PNe (R) are a minority (22 % of all Galactic PNe with studied morphology) 49% elliptical (E) 17% bipolar (or multi-polar) (B) 9% have an equatorial enhancement, or ring (lobe-less bipolar, or bipolar cores) (BC) 3% point-symmetric Symmetric | Asymmetric

  7. HST and spatial resolution LMC SMP 10 HST STIS -----3 arcsec ------- ------------35 arcsec ----------------------

  8. Slitless Spectra of LMC SMP 16 G430M (4818—5104) and G750M (6295—6867) _4959 [O III] _5007 [O III] _4861 Hb _6300 [O I] 6584 [N II] 6563 Ha 6548 [N II] 6732 [S II] 6716 [S II]

  9. Galaxy LMC SMC Round Elliptical Bipolar Point-symmetric Symmetric | Asymmetric

  10. Morphological distribution

  11. What is the physical origin of the equatorial disks? • stellar rotation? Maybe associated with • a strong magnetic field? Garcia-Segura 97 (single magnetic WD are more massive than non-magnetic WDs! Wickramasinge & Ferrario 2000) • Binary evolution of the progenitor (CE)? Morris 81; Soker 98

  12. Chemistry • PNe enrich the ISM • He, C, N, O abundances are linked to the evolution of the progenitors • C-rich for massive progenitors (MZAMS < 3 Msun) • He- and N-rich (and C-poor) if MZAMS > 3 Msun • Ar, S, Ne are invariant during the evolution of stars in this mass range  they are signature of the protostellar ambient, thus test previous evolutionary history Planetary nebulae beyond the Milky Way - May 19-21, 2004

  13. O Round * Elliptical Bipolar core  Bipolar  LMC HII regions (average) Primordial elements, LMC

  14. ORound * Elliptical Bipolar core  Bipolar  LMC HII regions (average) Primordial elements, LMC

  15. LMC PN morphology and the products of stellar evolution ORound * Elliptical  Bipolar core  Bipolar •  LMC HII regions (average)

  16. SMP16 SMP 95 SMP 34 Decreasing excitation class ---> Si IV N IV C IV] He II

  17. [Ne IV] SMP16 SMP 95 SMP 34 C III ] C II]

  18. Optical AND UV morphology Broad band [O III] 5007 [N II] Ha [N II] C III]1908 C II] 2327 [Ne IV] 2426 nebular continuum LMC SMP 95

  19. UV spectra fitting Planetary nebulae beyond the Milky Way - May 19-21, 2004

  20. P-Cygni profiles Planetary nebulae beyond the Milky Way - May 19-21, 2004

  21. Wind momentum vs. luminosity See poster by A. Arrieta

  22. Transition time • Transition time (ttr) is measured from the envelope ejection quenching (EEQ) and the PN illumination; it is regulated by wind and/or nuclear evolution • MeR (residual envelope mass at EEQ) determines ttr • tdyn =DPN/vexp represent the dynamic PN age. If DPN is measured on main shell, tdyn tracks time from EEQ • tdyn =ttr+ tev (tev= time after PN illumination, corresponding to evolutionary time if tracks have zero point at illumination)

  23. Dealing with unsynchronized clocks • ttr is an essential parameter in post-AGB population synthesis (e.g., PNLF high luminosity cutoff, and UV contribution from post-AGB stars in galaxies) • Mass-loss at TP-AGB and beyond not completely understood, and MeR now known • Only way to constraint ttr is observationally • > Magellanic PNe offer the first direct estimates of transition time • Assumptions: no acceleration of shells; He-tracks scaled to H-burning tracks Planetary nebulae beyond the Milky Way - May 19-21, 2004

  24. tdyn and tev LMC SMC Round: symm. PNe (R,E) Square: asymm. PNe (B,BC,P) H-burning central stars

  25. Distribution of ttr in MC PNe

  26. MeR=2e-3 MeR=1e-3 Data LMC PNe SMC Pne Models twind tnucl ttr MeR=5e-3 MeR=1e-2

  27. Total mass loss (IMFMR) Data: optically thin LMC and SMC PNe Hydro models: solid line =PN shells broken line=outer halos --> To constrain IMFMR we need to measure mass in PN halos (and in CSs)

  28. Importance of spatially-resolved PN populations • We sampled ~50 (+30) LMC and ~30 SMC PNe, chosen among the brightest known (based on on Hb and [O III] 5007 fluxes ) • All LMC PN candidates are indeed PNe • ~10% of the SMC PN candidates are H II regions Planetary nebulae beyond the Milky Way - May 19-21, 2004

  29. MA 1796 MA 1797 MG 2 Log Fb -13.85 ... -14.3 C 1.53 ... 1.4 Size [arcsec] 3 11 3.5 Size [pc] 0.85 3.1 0.98 Planetary nebulae beyond the Milky Way - May 19-21, 2004

  30. LMC SMC Observed distributions of I(5007)/I(Hb)

  31. Cloudy models Galaxy LMC SMC

  32. Galaxy SMC LMC PN cooling in different galaxies Our HST data: LMC <I(5007)/I(Hb)>=9.4 (3.1) <I(1909)/I(Hb)>=5 (5) SMC <I(5007)/I(Hb)>=5.7 (2.5) UV: Cycle 13

  33. PNe in the PNLF O round; * elliptical; bipolar core;  bipolar LMCSMC Open circles: R Asterisks: E Triangles: BC Squares: B Filled circles: P Faint----------> bright

  34. CSs in PNLF LMC SMC Faint-----------> bright SMC HLCO LMC HLCO

  35. Summary, and the future • HST fundamental for shapes/ radii, but also for identification (misclassified H II regions in SMC but not in LMC  metallicity effect?) • Same morphology types in Galaxy, LMC, SMC, but more asymmetric PNe in LMC than SMC  different stellar generations? • Asymmetric LMC PNe have high Ne, S, Ar--> signature of younger progenitors • Similar UV and optical morphology Planetary nebulae beyond the Milky Way - May 19-21, 2004

  36. Summary, cont. • Carbon higher for symmetric PNe, STIS UV spectra of LMC PNe to be analyzed; SMC PNe in Cycle 13 • P-Cygni profiles as signature of CS winds, distance indicator for galactic PNe • Transition time constrained from observation enlarge sample, hydro+stellar modeling • IMFM relation constraints • [O III]/Hb flux ratio of a PN population variant with host galaxy Planetary nebulae beyond the Milky Way - May 19-21, 2004

  37. Summary, cont. • Symmetric PNe populate the high luminosity parts of the PNLF • High mass CSs populate the faint end of the LF, sample to be extended Planetary nebulae beyond the Milky Way - May 19-21, 2004

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