Magellanic Cloud planetary nebulae as probes of stellar evolution - PowerPoint PPT Presentation

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

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 2 Planetary nebulae beyond the Milky Way - May 19-21, 2004

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

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

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? 5 Planetary nebulae beyond the Milky Way - May 19-21, 2004

Round PNe (R) are a minority (22 % of all Galactic PNe with studied morphology) Symmetric | Asymmetric 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 6

HST and spatial resolution LMC SMP 10 HST STIS � -----3 arcsec ------- � 7 � ------------35 arcsec ---------------------- �

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

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

Morphological distribution LMC SMC Round R 29 % 35 % Elliptical E 17 % 29 % R+E (symm.) 46 % 64 % Bipolar B 34 % 6 % Bipolar core BC 17 % 24 % B+BC (asymm.) 51 % 30 % Point-symmetric 3 % 6 % 10

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 11

Chemistry · PNe enrich the ISM · He, C, N, O abundances are linked to the evolution of the progenitors · C-rich for massive progenitors (M ZAMS < 3 Msun) · He- and N-rich (and C-poor) if M ZAMS > 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 12 Planetary nebulae beyond the Milky Way - May 19-21, 2004

Primordial elements, LMC O Round * Elliptical � Bipolar core � Bipolar ⊗ LMC HII regions (average) 13

Primordial elements, LMC O Round * Elliptical � Bipolar core Bipolar � ⊗ LMC HII regions (average) 14

LMC PN morphology and the products of stellar evolution O Round * Elliptical � Bipolar core � Bipolar ⊗ LMC HII regions (average) 15

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

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

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

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

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

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

Transition time · Transition time (t tr ) is measured from the envelope ejection quenching (EEQ) and the PN illumination; it is regulated by wind and/or nuclear evolution · M eR (residual envelope mass at EEQ) determines t tr • τ dyn =D PN /v exp represent the dynamic PN age. If D PN is measured on main shell, τ dyn tracks time from EEQ • τ dyn =t tr + t ev (t ev = time after PN illumination, corresponding to evolutionary time if tracks have zero point at illumination) 22

Dealing with unsynchronized clocks · t tr 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 M eR now known · Only way to constraint t tr is observationally · > Magellanic PNe offer the first direct estimates of transition time 23 Planetary nebulae beyond the Milky Way - May 19-21, 2004

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

Distribution of t tr in MC PNe 25

M e R =2e-3 M e R =1e-3 Data LMC PNe SMC Pne Models M e R =5e-3 M e R =1e-2 t wind t nucl t tr 26

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) 27

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

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

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

Cloudy models Galaxy LMC SMC PN + CS trans. Super-wind Nuclear reactions end TP-AGB AGB Cooling WD L T eff 31

Cloudy models, varying density SMC LMC Galaxy 32

PN cooling in different galaxies Our HST data: LMC <I(5007)/I(H β )>=9.4 (3.1) <I(1909)/I(H β )>=5 (5) SMC <I(5007)/I(H β )>=5.7 (2.5) UV: Cycle 13 Galaxy SMC LMC 33

PNe in the PNLF O round; * elliptical; � bipolar core; � bipolar LMC SMC Open circles: R Faint----------> bright Asterisks: E Triangles: BC Squares: B Filled circles: P 34

CSs in PNLF Faint-----------> bright LMC SMC 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 36 Planetary nebulae beyond the Milky Way - May 19-21, 2004

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]/H β flux ratio of a PN population variant with host galaxy 37 Planetary nebulae beyond the Milky Way - May 19-21, 2004

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 38 Planetary nebulae beyond the Milky Way - May 19-21, 2004