Abundances in Asymmetric PNe: confrontation to AGB models Letizia Stanghellini, NOAO Special thanks: Martin Guerrero, Katia Cunha, Arturo Manchado, Eva Villaver, Bruce Balick, Ting-Hui Lee, Dick Shaw, Pedro Garcia-Lario, Jose Perea-Calderon, Anibal Garcia-Hernandez, James Davies, Amanda Karakas

PNe are probes of stellar evolution –The composition of PNe reflects their progenitors evolutionary paths –Stars that go through the AGB phase may be the principal producers of nitrogen, and supply as much carbon as massive stars –It is essential that any hypothesis of formation of asymmetric PNe takes into account the comparison between PN abundances and evolutionary yields

Selected sample and references Galactic disk (205 PNe) –Abundances Stanghellini et al. 06 (homogeneous sample, excludes bulge and halo PNe) –Morphology (R, E, B, BC) IAC Morphological Catalog, Manchado et al. 96 Magellanic Clouds (108 LMC and 35 SMC PNe) –Abundances Leisy & Dennefeld 96; Stanghellini et al. 05, 07 Henry et al. 89; Monk et al. 89; Boroson & Liebert 89; Stasinska et al. 98 –Morphology (R, E, B, BC) HST database (Shaw et al. 01, 07; Stanghellini et al. 99, 02)

MW DiskLMCSMC He/H symmetric (R, E) asymm. (B, BC) C/H [10 4 ] symmetric (R, E) asymm. (B, BC) N/H [10 4 ] symmetric (R, E) asymm. (B, BC) bipolars (B) O/H [10 4 ] symmetric (R, E) asymm. (B, BC) N/O symmetric (R, E) asymm. (B, BC) bipolars

Galactic PNe and AGB models Symmetric PNe Asymmetric PNe Yields from AGB Models    Karakas 1< M to < 4, Z=0.016 Karakas 4 < M to < 6.5, Z=0.016    Gavilan 5 < M to < < Z < (synthetic, extrapolated models)

LMC PNe and AGB models Symmetric PNe Asymmetric PNe Yields from AGB Models    Karakas 1< M to < 4, Z=0.08 Karakas 4 < M to < 6.5, Z=0.08

SMC PNe and AGB models Symmetric PNe Asymmetric PNe Yields from AGB Models    Karakas 1< M to < 4, Z=0.04 Karakas 4 < M to < 6.5, Z=0.04

Three populations He/H and N/O averages, homogeneous data samples. Bars represent data ranges

Symmetric PNe Asymmetric PNe Yields from AGB Models    Karakas 1< M to < 4, Z=0.008 Karakas 4 < M to < 5, Z=0.008    Gavilan 5 < M to < < Z < Carbon and LMC PNe

Spitzer IRS spectra ~40 LMC and SMC PN spectra (GO2); half of the PNe have nebular line-dominated spectra; The other PNe show C-rich dust features (CRD, 90%) or O-rich dust features (ORD, 10%) CRDORD

Left panels: Triangles: featureless Diamonds: CRD Squares: ORD Right panels: Circles: R Diamonds: E Triangles: BC Squares: B Only symmetric PNe have CRD spectra, and only asymmetric PNe have ORD Spectra Stanghellini et al. 2007, to Appear on ApJ

Left panels: Triangles: featureless Diamonds: CRD Squares: ORD Right panels: Circles: R Diamonds: E Triangles: BC Squares: B

Conclusions PN observations compared to AGB evolution shows that asymmetric PNe have massive AGB progenitors, lower mass limit depends on metallicity A small fraction of asymmetric PNe might derive from low-mass binary evolution, where N production is stopped as the members do not suffer third dredge-up Spitzer spectra show that gas and dust chemistry are compatible with this scenario